[svn-r30313] HDFFV-9972: unsatisfied link error under debug on Windows.

Added windows name suffix for debug to CMake cmd_arg for examples and test.
Fix issues discovered under debug testing;
   Create a version of H5Iget_name that correctly returns the name.
   Rework PIN_JAVA_STRING macro and usage to eliminate possible memory leaks by using if-else instead of mid-routine return.
   Update example to use new H5Iget_name API.
   
   Tested: windows under debug

24 files changed, 1626 insertions, 1632 deletions

diff --git a/java/examples/datasets/CMakeLists.txt b/java/examples/datasets/CMakeLists.txt
index 5f5f37c..0ba2331 100644
--- a/java/examples/datasets/CMakeLists.txt
+++ b/java/examples/datasets/CMakeLists.txt
@@ -63,7 +63,11 @@ endforeach (HDFJAVA_JAR)
 
 MACRO (ADD_H5_TEST resultfile resultcode)
   if (CMAKE_BUILD_TYPE MATCHES Debug)
-    set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    if (WIN32)
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_D;")
+    else()
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    endif()
   endif(CMAKE_BUILD_TYPE MATCHES Debug)
   add_test (
       NAME JAVA_datasets-${resultfile}
diff --git a/java/examples/datatypes/CMakeLists.txt b/java/examples/datatypes/CMakeLists.txt
index 1e305be..5ab513c 100644
--- a/java/examples/datatypes/CMakeLists.txt
+++ b/java/examples/datatypes/CMakeLists.txt
@@ -63,7 +63,11 @@ endforeach (HDFJAVA_JAR)
 
 MACRO (ADD_H5_TEST resultfile resultcode)
   if (CMAKE_BUILD_TYPE MATCHES Debug)
-    set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    if (WIN32)
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_D;")
+    else()
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    endif()
   endif(CMAKE_BUILD_TYPE MATCHES Debug)
   add_test (
       NAME JAVA_datatypes-${resultfile}
diff --git a/java/examples/datatypes/H5Ex_T_ObjectReference.java b/java/examples/datatypes/H5Ex_T_ObjectReference.java
index 3cad6c9..8a09f5b 100644
--- a/java/examples/datatypes/H5Ex_T_ObjectReference.java
+++ b/java/examples/datatypes/H5Ex_T_ObjectReference.java
@@ -256,11 +256,10 @@ public class H5Ex_T_ObjectReference {
                     object_id = H5.H5Rdereference(dataset_id, HDF5Constants.H5P_DEFAULT, HDF5Constants.H5R_OBJECT, dset_data[indx]);
                     object_type = H5.H5Rget_obj_type(dataset_id, HDF5Constants.H5R_OBJECT, dset_data[indx]);
                 }
-                String[] obj_name = new String[1];
-                long name_size = 1;
+                String obj_name = null;
                 if (object_type >= 0) {
                     // Get the length of the name and retrieve the name.
-                    name_size = 1 + H5.H5Iget_name(object_id, obj_name, name_size);
+                    obj_name = H5.H5Iget_name(object_id);
                 }
                 if ((object_id >= 0) && (object_type >= -1)) {
                     switch (H5G_obj.get(object_type)) {
@@ -299,8 +298,7 @@ public class H5Ex_T_ObjectReference {
                     }
                 }
                 // Print the name.
-                if (name_size > 1)
-                    System.out.println(": " + obj_name[0]);
+                System.out.println(": " + obj_name);
             }
             catch (Exception e) {
                 e.printStackTrace();
diff --git a/java/examples/datatypes/H5Ex_T_ObjectReferenceAttribute.java b/java/examples/datatypes/H5Ex_T_ObjectReferenceAttribute.java
index e354029..e366681 100644
--- a/java/examples/datatypes/H5Ex_T_ObjectReferenceAttribute.java
+++ b/java/examples/datatypes/H5Ex_T_ObjectReferenceAttribute.java
@@ -289,11 +289,10 @@ public class H5Ex_T_ObjectReferenceAttribute {
                     object_id = H5.H5Rdereference(dataset_id, HDF5Constants.H5P_DEFAULT, HDF5Constants.H5R_OBJECT, dset_data[indx]);
                     object_type = H5.H5Rget_obj_type(dataset_id, HDF5Constants.H5R_OBJECT, dset_data[indx]);
                 }
-                String[] obj_name = new String[1];
-                long name_size = 1;
+                String obj_name = null;
                 if (object_type >= 0) {
                     // Get the length of the name and retrieve the name.
-                    name_size = 1 + H5.H5Iget_name(object_id, obj_name, name_size);
+                    obj_name = H5.H5Iget_name(object_id);
                 }
                 if ((object_id >= 0) && (object_type >= -1)) {
                     switch (H5G_obj.get(object_type)) {
@@ -332,8 +331,7 @@ public class H5Ex_T_ObjectReferenceAttribute {
                     }
                 }
                 // Print the name.
-                if (name_size > 1)
-                    System.out.println(": " + obj_name[0]);
+                System.out.println(": " + obj_name);
             }
             catch (Exception e) {
                 e.printStackTrace();
diff --git a/java/examples/groups/CMakeLists.txt b/java/examples/groups/CMakeLists.txt
index 410168a..c23b7d3 100644
--- a/java/examples/groups/CMakeLists.txt
+++ b/java/examples/groups/CMakeLists.txt
@@ -62,7 +62,11 @@ add_custom_target(H5Ex_G_Visit_files ALL COMMENT "Copying files needed by H5Ex_G
 
 MACRO (ADD_H5_TEST resultfile resultcode)
   if (CMAKE_BUILD_TYPE MATCHES Debug)
-    set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    if (WIN32)
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_D;")
+    else()
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    endif()
   endif(CMAKE_BUILD_TYPE MATCHES Debug)
   add_test (
       NAME JAVA_groups-${resultfile}
diff --git a/java/examples/intro/CMakeLists.txt b/java/examples/intro/CMakeLists.txt
index 8679943..6b77382 100644
--- a/java/examples/intro/CMakeLists.txt
+++ b/java/examples/intro/CMakeLists.txt
@@ -64,7 +64,11 @@ endforeach (example ${HDF_JAVA_OBJECT_EXAMPLES})
 
 MACRO (ADD_H5_TEST resultfile resultcode)
   if (CMAKE_BUILD_TYPE MATCHES Debug)
-    set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    if (WIN32)
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_D;")
+    else()
+      set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+    endif()
   endif(CMAKE_BUILD_TYPE MATCHES Debug)
   add_test (
       NAME JAVA_intro-${resultfile}
diff --git a/java/src/hdf/hdf5lib/H5.java b/java/src/hdf/hdf5lib/H5.java
index e4144c9..e5defe3 100644
--- a/java/src/hdf/hdf5lib/H5.java
+++ b/java/src/hdf/hdf5lib/H5.java
@@ -3351,8 +3351,22 @@ public class H5 implements java.io.Serializable {
 
     public synchronized static native long H5Iget_file_id(long obj_id) throws HDF5LibraryException;
 
+    @Deprecated
     public synchronized static native long H5Iget_name(long obj_id, String[] name, long size)
             throws HDF5LibraryException, NullPointerException;
+    /**
+     * H5Iget_name_str retrieves the name of an object specified by the identifier, obj_id.
+     *
+     * @param obj_id
+     *            IN: Identifier of the object.
+     *
+     * @return String for Attribute name.
+     *
+     * @exception HDF5LibraryException
+     *                - Error from the HDF-5 Library.
+     **/
+    public synchronized static native String H5Iget_name_str(long obj_id)
+            throws HDF5LibraryException;
 
     public synchronized static native int H5Iget_ref(long obj_id) throws HDF5LibraryException, NullPointerException;
 
diff --git a/java/src/jni/CMakeLists.txt b/java/src/jni/CMakeLists.txt
index ef80072..2e4a821 100644
--- a/java/src/jni/CMakeLists.txt
+++ b/java/src/jni/CMakeLists.txt
@@ -57,6 +57,9 @@ SET_GLOBAL_VARIABLE (HDF5_LIBRARIES_TO_EXPORT "${HDF5_LIBRARIES_TO_EXPORT};${HDF
 H5_SET_LIB_OPTIONS (${HDF5_JAVA_JNI_LIB_TARGET} ${HDF5_JAVA_JNI_LIB_NAME} SHARED ${HDF5_JAVA_PACKAGE_SOVERSION})
 if (WIN32)
   get_filename_component (HDF5_JAVA_JNI_DLL_NAME ${HDF5_JAVA_JNI_LIB_TARGET} NAME_WE)
+  if (CMAKE_BUILD_TYPE MATCHES Debug)
+    set (HDF5_JAVA_JNI_DLL_NAME "${HDF5_JAVA_JNI_DLL_NAME}_D")
+  endif ()
   # message (STATUS "HDF5_JAVA_JNI_DLL_NAME: ${HDF5_JAVA_JNI_DLL_NAME}")
   if (BUILD_TESTING)
     add_custom_target (HDF5_JAVA_JNI-Test-Copy ALL
diff --git a/java/src/jni/h5aImp.c b/java/src/jni/h5aImp.c
index 5af60fb..5af8aae 100644
--- a/java/src/jni/h5aImp.c
+++ b/java/src/jni/h5aImp.c
@@ -67,14 +67,15 @@ Java_hdf_hdf5lib_H5__1H5Acreate
     hid_t       attr_id = -1;
     const char *aName;
 
-    PIN_JAVA_STRING(name, aName, -1);
+    PIN_JAVA_STRING(name, aName);
+    if (aName != NULL) {
+        attr_id = H5Acreate2((hid_t)loc_id, aName, (hid_t)type_id, (hid_t)space_id, (hid_t)create_plist, (hid_t)H5P_DEFAULT);
 
-    attr_id = H5Acreate2((hid_t)loc_id, aName, (hid_t)type_id, (hid_t)space_id, (hid_t)create_plist, (hid_t)H5P_DEFAULT);
+        UNPIN_JAVA_STRING(name, aName);
 
-    UNPIN_JAVA_STRING(name, aName);
-
-    if (attr_id < 0)
-        h5libraryError(env);
+        if (attr_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)attr_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Acreate */
@@ -91,14 +92,15 @@ Java_hdf_hdf5lib_H5__1H5Aopen_1name
     hid_t       attr_id = -1;
     const char *aName;
 
-    PIN_JAVA_STRING(name, aName, -1);
+    PIN_JAVA_STRING(name, aName);
+    if (aName != NULL) {
+        attr_id = H5Aopen_name((hid_t)loc_id, aName);
 
-    attr_id = H5Aopen_name((hid_t)loc_id, aName);
+        UNPIN_JAVA_STRING(name,aName);
 
-    UNPIN_JAVA_STRING(name,aName);
-
-    if (attr_id < 0)
-        h5libraryError(env);
+        if (attr_id < 0)
+            h5libraryError(env);
+        }
 
     return (jlong)attr_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Aopen_1name */
@@ -242,8 +244,7 @@ Java_hdf_hdf5lib_H5_H5Aget_1name
     ssize_t  buf_size;
 
     /* get the length of the name */
-    buf_size = H5Aget_name((hid_t)attr_id, NULL, 0);
-
+    buf_size = H5Aget_name((hid_t)attr_id, 0, NULL);
     if (buf_size <= 0) {
         h5badArgument(env, "H5Aget_name:  buf_size <= 0");
     } /* end if */
@@ -299,14 +300,15 @@ Java_hdf_hdf5lib_H5_H5Adelete
     herr_t      status = -1;
     const char *aName;
 
-    PIN_JAVA_STRING(name, aName, -1);
-
-    status = H5Adelete((hid_t)loc_id, aName);
+    PIN_JAVA_STRING(name, aName);
+    if (aName != NULL) {
+        status = H5Adelete((hid_t)loc_id, aName);
 
-    UNPIN_JAVA_STRING(name, aName);
+        UNPIN_JAVA_STRING(name, aName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Adelete */
@@ -344,15 +346,16 @@ Java_hdf_hdf5lib_H5__1H5Acreate2
     hid_t       status = -1;
     const char *aName;
 
-    PIN_JAVA_STRING(name, aName, -1);
+    PIN_JAVA_STRING(name, aName);
+    if (aName != NULL) {
+        status = H5Acreate2((hid_t)loc_id, aName, (hid_t)type_id,
+            (hid_t)space_id, (hid_t)create_plist, (hid_t)access_plist );
 
-    status = H5Acreate2((hid_t)loc_id, aName, (hid_t)type_id,
-        (hid_t)space_id, (hid_t)create_plist, (hid_t)access_plist );
+        UNPIN_JAVA_STRING(name, aName);
 
-    UNPIN_JAVA_STRING(name, aName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)status;
 } /* end Java_hdf_hdf5lib_H5__1H5Acreate2 */
@@ -371,14 +374,15 @@ Java_hdf_hdf5lib_H5__1H5Aopen
     hid_t       retVal = -1;
     const char *aName;
 
-    PIN_JAVA_STRING(name, aName, -1);
+    PIN_JAVA_STRING(name, aName);
+    if (aName != NULL) {
+        retVal = H5Aopen((hid_t)obj_id, aName, (hid_t)access_plist);
 
-    retVal = H5Aopen((hid_t)obj_id, aName, (hid_t)access_plist);
+        UNPIN_JAVA_STRING(name, aName);
 
-    UNPIN_JAVA_STRING(name, aName);
-
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)retVal;
 } /* end Java_hdf_hdf5lib_H5__1H5Aopen */
@@ -395,15 +399,16 @@ Java_hdf_hdf5lib_H5__1H5Aopen_1by_1idx
     hid_t       retVal = -1;
     const char *aName;
 
-    PIN_JAVA_STRING(name, aName, -1);
-
-    retVal = H5Aopen_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
-            (H5_iter_order_t)order, (hsize_t)n, (hid_t)aapl_id, (hid_t)lapl_id);
+    PIN_JAVA_STRING(name, aName);
+    if (aName != NULL) {
+        retVal = H5Aopen_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
+                (H5_iter_order_t)order, (hsize_t)n, (hid_t)aapl_id, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING(name, aName);
+        UNPIN_JAVA_STRING(name, aName);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)retVal;
 } /* end Java_hdf_hdf5lib_H5__1H5Aopen_1by_1idx */
@@ -421,15 +426,16 @@ Java_hdf_hdf5lib_H5__1H5Acreate_1by_1name
     const char *aName;
     const char *attrName;
 
-    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName, -1);
-
-    retVal = H5Acreate_by_name((hid_t)loc_id, aName, attrName, (hid_t)type_id,
-            (hid_t)space_id, (hid_t)acpl_id, (hid_t)aapl_id, (hid_t)lapl_id);
+    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
+    if (aName != NULL && attrName != NULL) {
+        retVal = H5Acreate_by_name((hid_t)loc_id, aName, attrName, (hid_t)type_id,
+                (hid_t)space_id, (hid_t)acpl_id, (hid_t)aapl_id, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
+        UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)retVal;
 } /* end Java_hdf_hdf5lib_H5__1H5Acreate_1by_1name */
@@ -443,20 +449,23 @@ JNIEXPORT jboolean JNICALL
 Java_hdf_hdf5lib_H5_H5Aexists_1by_1name
     (JNIEnv *env, jclass clss, jlong loc_id, jstring obj_name, jstring attr_name, jlong lapl_id)
 {
-    htri_t      retVal = -1;
+    htri_t      bval = JNI_FALSE;
     const char *aName;
     const char *attrName;
 
-    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName, JNI_FALSE);
-
-    retVal = H5Aexists_by_name((hid_t)loc_id, aName, attrName, (hid_t)lapl_id);
+    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
+    if (aName != NULL && attrName != NULL) {
+        bval = H5Aexists_by_name((hid_t)loc_id, aName, attrName, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
+        UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (bval > 0)
+            bval = JNI_TRUE;
+        else if (bval < 0)
+            h5libraryError(env);
+    }
 
-    return (jboolean)retVal;
+    return (jboolean)bval;
 } /* end Java_hdf_hdf5lib_H5_H5Aexists_1by_1name */
 
 /*
@@ -472,14 +481,15 @@ Java_hdf_hdf5lib_H5_H5Arename
     const char *oName;
     const char *nName;
 
-    PIN_JAVA_STRING_TWO(old_attr_name, oName, new_attr_name, nName, -1);
-
-    retVal = H5Arename((hid_t)loc_id, oName, nName);
+    PIN_JAVA_STRING_TWO(old_attr_name, oName, new_attr_name, nName);
+    if (oName != NULL && nName != NULL) {
+        retVal = H5Arename((hid_t)loc_id, oName, nName);
 
-    UNPIN_JAVA_STRING_TWO(old_attr_name, oName, new_attr_name, nName);
+        UNPIN_JAVA_STRING_TWO(old_attr_name, oName, new_attr_name, nName);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Arename */
@@ -499,14 +509,15 @@ Java_hdf_hdf5lib_H5_H5Arename_1by_1name
     const char *oName;
     const char *nName;
 
-    PIN_JAVA_STRING_THREE(obj_name, aName, old_attr_name, oName, new_attr_name, nName, -1);
-
-    retVal = H5Arename_by_name((hid_t)loc_id, aName, oName, nName, (hid_t)lapl_id);
+    PIN_JAVA_STRING_THREE(obj_name, aName, old_attr_name, oName, new_attr_name, nName);
+    if (aName != NULL && oName != NULL && nName != NULL) {
+        retVal = H5Arename_by_name((hid_t)loc_id, aName, oName, nName, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING_THREE(obj_name, aName, old_attr_name, oName, new_attr_name, nName);
+        UNPIN_JAVA_STRING_THREE(obj_name, aName, old_attr_name, oName, new_attr_name, nName);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Arename_1by_1name */
@@ -526,44 +537,45 @@ Java_hdf_hdf5lib_H5_H5Aget_1name_1by_1idx
     jstring  str = NULL;
     const char *aName;
 
-    PIN_JAVA_STRING(obj_name, aName, NULL);
+    PIN_JAVA_STRING(obj_name, aName);
+    if (aName != NULL) {
+        /* get the length of the attribute name */
+        status_size = H5Aget_name_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
+                (H5_iter_order_t) order, (hsize_t) n, (char*)NULL, (size_t)0, (hid_t)lapl_id);
 
-    /* get the length of the attribute name */
-    status_size = H5Aget_name_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
-            (H5_iter_order_t) order, (hsize_t) n, (char*)NULL, (size_t)0, (hid_t)lapl_id);
-
-    if(status_size < 0) {
-        UNPIN_JAVA_STRING(obj_name, aName);
-        h5libraryError(env);
-    } /* end if */
-    else {
-        buf_size = (size_t)status_size + 1;/* add extra space for the null terminator */
-
-        aValue = (char*)HDmalloc(sizeof(char) * buf_size);
-        if (aValue == NULL) {
+        if(status_size < 0) {
             UNPIN_JAVA_STRING(obj_name, aName);
-            h5outOfMemory(env, "H5Aget_name_by_idx:  malloc failed ");
+            h5libraryError(env);
         } /* end if */
         else {
-            status_size = H5Aget_name_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
-                    (H5_iter_order_t) order, (hsize_t) n, (char*)aValue, (size_t)buf_size, (hid_t)lapl_id);
-
-            UNPIN_JAVA_STRING(obj_name, aName);
+            buf_size = (size_t)status_size + 1;/* add extra space for the null terminator */
 
-            if (status_size < 0) {
-                HDfree(aValue);
-                h5libraryError(env);
+            aValue = (char*)HDmalloc(sizeof(char) * buf_size);
+            if (aValue == NULL) {
+                UNPIN_JAVA_STRING(obj_name, aName);
+                h5outOfMemory(env, "H5Aget_name_by_idx:  malloc failed ");
             } /* end if */
             else {
-                str = ENVPTR->NewStringUTF(ENVPAR aValue);
-                HDfree(aValue);
-                if (str == NULL) {
-                    /* exception -- fatal JNI error */
-                    h5JNIFatalError(env, "H5Aget_name_by_idx:  return string not created");
+                status_size = H5Aget_name_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
+                        (H5_iter_order_t) order, (hsize_t) n, (char*)aValue, (size_t)buf_size, (hid_t)lapl_id);
+
+                UNPIN_JAVA_STRING(obj_name, aName);
+
+                if (status_size < 0) {
+                    HDfree(aValue);
+                    h5libraryError(env);
                 } /* end if */
+                else {
+                    str = ENVPTR->NewStringUTF(ENVPAR aValue);
+                    HDfree(aValue);
+                    if (str == NULL) {
+                        /* exception -- fatal JNI error */
+                        h5JNIFatalError(env, "H5Aget_name_by_idx:  return string not created");
+                    } /* end if */
+                } /* end else */
             } /* end else */
         } /* end else */
-    } /* end else */
+    }
     return str;
 } /* end Java_hdf_hdf5lib_H5_H5Aget_1name_1by_1idx */
 
@@ -628,23 +640,24 @@ Java_hdf_hdf5lib_H5_H5Aget_1info_1by_1idx
     jobject     ret_obj = NULL;
     const char *aName;
 
-    PIN_JAVA_STRING(obj_name, aName, NULL);
+    PIN_JAVA_STRING(obj_name, aName);
+    if (aName != NULL) {
+        status = H5Aget_info_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
+                (H5_iter_order_t)order, (hsize_t)n, &ainfo, (hid_t)lapl_id);
 
-    status = H5Aget_info_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type,
-            (H5_iter_order_t)order, (hsize_t)n, &ainfo, (hid_t)lapl_id);
-
-    UNPIN_JAVA_STRING(obj_name, aName);
+        UNPIN_JAVA_STRING(obj_name, aName);
 
-    if (status < 0) {
-       h5libraryError(env);
-    } /* end if */
-    else {
-        args[0].z = ainfo.corder_valid;
-        args[1].j = ainfo.corder;
-        args[2].i = ainfo.cset;
-        args[3].j = (jlong)ainfo.data_size;
-        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5A_info_t", "(ZJIJ)V", args);
-    } /* end else */
+        if (status < 0) {
+        h5libraryError(env);
+        } /* end if */
+        else {
+            args[0].z = ainfo.corder_valid;
+            args[1].j = ainfo.corder;
+            args[2].i = ainfo.cset;
+            args[3].j = (jlong)ainfo.data_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5A_info_t", "(ZJIJ)V", args);
+        } /* end else */
+    }
     return ret_obj;
 } /* end Java_hdf_hdf5lib_H5_H5Aget_1info_1by_1idx */
 
@@ -664,22 +677,23 @@ Java_hdf_hdf5lib_H5_H5Aget_1info_1by_1name
     jvalue      args[4];
     jobject     ret_obj = NULL;
 
-    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName, NULL);
+    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
+    if (aName != NULL && attrName != NULL) {
+        status = H5Aget_info_by_name((hid_t)loc_id, aName, attrName, &ainfo, (hid_t)lapl_id);
 
-    status = H5Aget_info_by_name((hid_t)loc_id, aName, attrName, &ainfo, (hid_t)lapl_id);
+        UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
 
-    UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
-
-    if (status < 0) {
-       h5libraryError(env);
-    } /* end if */
-    else {
-        args[0].z = ainfo.corder_valid;
-        args[1].j = ainfo.corder;
-        args[2].i = ainfo.cset;
-        args[3].j = (jlong)ainfo.data_size;
-        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5A_info_t", "(ZJIJ)V", args);
-    } /* end else */
+        if (status < 0) {
+        h5libraryError(env);
+        } /* end if */
+        else {
+            args[0].z = ainfo.corder_valid;
+            args[1].j = ainfo.corder;
+            args[2].i = ainfo.cset;
+            args[3].j = (jlong)ainfo.data_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5A_info_t", "(ZJIJ)V", args);
+        } /* end else */
+    }
     return ret_obj;
 } /* end Java_hdf_hdf5lib_H5_H5Aget_1info_1by_1name */
 
@@ -696,14 +710,15 @@ Java_hdf_hdf5lib_H5_H5Adelete_1by_1name
     const char *aName;
     const char *attrName;
 
-    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName, -1);
-
-    retVal = H5Adelete_by_name((hid_t)loc_id, aName, attrName, (hid_t)lapl_id);
+    PIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
+    if (aName != NULL && attrName != NULL) {
+        retVal = H5Adelete_by_name((hid_t)loc_id, aName, attrName, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
+        UNPIN_JAVA_STRING_TWO(obj_name, aName, attr_name, attrName);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Adelete_1by_1name */
@@ -720,16 +735,17 @@ Java_hdf_hdf5lib_H5_H5Aexists
     htri_t      bval = JNI_FALSE;
     const char *aName;
 
-    PIN_JAVA_STRING(attr_name, aName, JNI_FALSE);
+    PIN_JAVA_STRING(attr_name, aName);
+    if (aName != NULL) {
+        bval = H5Aexists((hid_t)obj_id, aName);
 
-    bval = H5Aexists((hid_t)obj_id, aName);
+        UNPIN_JAVA_STRING(attr_name, aName);
 
-    UNPIN_JAVA_STRING(attr_name, aName);
-
-    if (bval > 0)
-        bval = JNI_TRUE;
-    else if (bval < 0)
-        h5libraryError(env);
+        if (bval > 0)
+            bval = JNI_TRUE;
+        else if (bval < 0)
+            h5libraryError(env);
+    }
 
     return (jboolean)bval;
 } /* end Java_hdf_hdf5lib_H5_H5Aexists */
@@ -746,14 +762,15 @@ Java_hdf_hdf5lib_H5_H5Adelete_1by_1idx
     herr_t      status = -1;
     const char *aName;
 
-    PIN_JAVA_STRING0(obj_name, aName);
-
-    status = H5Adelete_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type, (H5_iter_order_t)order, (hsize_t)n, (hid_t)lapl_id);
+    PIN_JAVA_STRING(obj_name, aName);
+    if (aName != NULL) {
+        status = H5Adelete_by_idx((hid_t)loc_id, aName, (H5_index_t)idx_type, (H5_iter_order_t)order, (hsize_t)n, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING(obj_name, aName);
+        UNPIN_JAVA_STRING(obj_name, aName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Adelete_1by_1idx */
 
 /*
@@ -770,14 +787,15 @@ Java_hdf_hdf5lib_H5__1H5Aopen_1by_1name
     const char *aName;
     const char *oName;
 
-    PIN_JAVA_STRING_TWO(obj_name, oName, attr_name, aName, -1);
-
-    status = H5Aopen_by_name((hid_t)loc_id, oName, aName, (hid_t)aapl_id, (hid_t)lapl_id);
+    PIN_JAVA_STRING_TWO(obj_name, oName, attr_name, aName);
+    if (oName != NULL && aName != NULL) {
+        status = H5Aopen_by_name((hid_t)loc_id, oName, aName, (hid_t)aapl_id, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING_TWO(obj_name, oName, attr_name, aName);
+        UNPIN_JAVA_STRING_TWO(obj_name, oName, attr_name, aName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)status;
 } /* end Java_hdf_hdf5lib_H5__1H5Aopen_1by_1name */
@@ -892,14 +910,15 @@ Java_hdf_hdf5lib_H5_H5Aiterate_1by_1name
         h5nullArgument(env,  "H5Literate_by_name:  op_data or callback_op is NULL");
     } /* end if */
     else {
-        PIN_JAVA_STRING(name, lName, -1);
+        PIN_JAVA_STRING(name, lName);
+        if (lName != NULL) {
+            status = H5Aiterate_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (hsize_t*)&start_idx, (H5A_operator2_t)H5A_iterate_cb, (void*)op_data, (hid_t)access_id);
 
-        status = H5Aiterate_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (hsize_t*)&start_idx, (H5A_operator2_t)H5A_iterate_cb, (void*)op_data, (hid_t)access_id);
+            UNPIN_JAVA_STRING(name, lName);
 
-        UNPIN_JAVA_STRING(name, lName);
-
-        if (status < 0)
-            h5libraryError(env);
+            if (status < 0)
+                h5libraryError(env);
+        }
     } /* end else */
 
     return (jint)status;
diff --git a/java/src/jni/h5dImp.c b/java/src/jni/h5dImp.c
index 2ef14df..ed1db41 100644
--- a/java/src/jni/h5dImp.c
+++ b/java/src/jni/h5dImp.c
@@ -161,14 +161,15 @@ Java_hdf_hdf5lib_H5__1H5Dcreate
     hid_t       dset_id = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        dset_id = H5Dcreate2((hid_t)loc_id, fileName, (hid_t)type_id, (hid_t)space_id, H5P_DEFAULT, (hid_t)create_plist_id, H5P_DEFAULT);
 
-    dset_id = H5Dcreate2((hid_t)loc_id, fileName, (hid_t)type_id, (hid_t)space_id, H5P_DEFAULT, (hid_t)create_plist_id, H5P_DEFAULT);
+        UNPIN_JAVA_STRING(name, fileName);
 
-    UNPIN_JAVA_STRING(name, fileName);
-
-    if (dset_id < 0)
-        h5libraryError(env);
+        if (dset_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)dset_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Dcreate */
@@ -185,13 +186,14 @@ Java_hdf_hdf5lib_H5__1H5Dopen
     hid_t       dset_id = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        dset_id = H5Dopen2((hid_t)loc_id, fileName, H5P_DEFAULT);
 
-    dset_id = H5Dopen2((hid_t)loc_id, fileName, H5P_DEFAULT);
-
-    UNPIN_JAVA_STRING(name, fileName);
-    if (dset_id < 0)
-        h5libraryError(env);
+        UNPIN_JAVA_STRING(name, fileName);
+        if (dset_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)dset_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Dopen */
@@ -285,7 +287,7 @@ Java_hdf_hdf5lib_H5_H5Dread
     (JNIEnv *env, jclass clss, jlong dataset_id, jlong mem_type_id, jlong mem_space_id,
           jlong file_space_id, jlong xfer_plist_id, jbyteArray buf, jboolean isCriticalPinning)
 {
-    herr_t   status;
+    herr_t   status = -1;
     jbyte   *buffP;
     jboolean isCopy;
     htri_t data_class;
@@ -341,7 +343,7 @@ Java_hdf_hdf5lib_H5_H5Dwrite
     (JNIEnv *env, jclass clss, jlong dataset_id, jlong mem_type_id, jlong mem_space_id,
           jlong file_space_id, jlong xfer_plist_id, jbyteArray buf, jboolean isCriticalPinning)
 {
-    herr_t   status;
+    herr_t   status = -1;
     jbyte   *buffP;
     jboolean isCopy;
     htri_t data_class;
@@ -1445,13 +1447,14 @@ Java_hdf_hdf5lib_H5__1H5Dcreate2
     hid_t       dset_id = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
-
-    dset_id = H5Dcreate2((hid_t)loc_id, fileName, (hid_t)type_id, (hid_t)space_id, (hid_t)link_plist_id, (hid_t)create_plist_id, (hid_t)access_plist_id);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        dset_id = H5Dcreate2((hid_t)loc_id, fileName, (hid_t)type_id, (hid_t)space_id, (hid_t)link_plist_id, (hid_t)create_plist_id, (hid_t)access_plist_id);
 
-    UNPIN_JAVA_STRING(name, fileName);
-    if (dset_id < 0)
-        h5libraryError(env);
+        UNPIN_JAVA_STRING(name, fileName);
+        if (dset_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)dset_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Dcreate2 */
@@ -1465,16 +1468,17 @@ JNIEXPORT jlong JNICALL
 Java_hdf_hdf5lib_H5__1H5Dopen2
     (JNIEnv *env, jclass clss, jlong loc_id, jstring name, jlong access_plist)
 {
-    hid_t       dset_id;
+    hid_t       dset_id = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        dset_id = H5Dopen2((hid_t)loc_id, fileName, (hid_t)access_plist);
 
-    dset_id = H5Dopen2((hid_t)loc_id, fileName, (hid_t)access_plist);
-
-    UNPIN_JAVA_STRING(name, fileName);
-    if (dset_id < 0)
-        h5libraryError(env);
+        UNPIN_JAVA_STRING(name, fileName);
+        if (dset_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)dset_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Dopen2 */
@@ -1585,39 +1589,40 @@ Java_hdf_hdf5lib_H5_H5Dfill
 
     if (buf == NULL) {
         h5nullArgument(env, "H5Dfill:  buf is NULL");
-        return;
     } /* end if */
-    buffP = ENVPTR->GetByteArrayElements(ENVPAR buf, &isCopy2);
-    if (buffP == NULL) {
-        h5JNIFatalError(env, "H5Dfill:  buf not pinned");
-        return;
-    } /* end if */
-
-    if(fill) {
-        fillP = ENVPTR->GetByteArrayElements(ENVPAR fill, &isCopy1);
-        if (fillP == NULL) {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, JNI_ABORT);
-            h5JNIFatalError( env, "H5Dfill:  fill not pinned");
-            return;
+    else {
+        buffP = ENVPTR->GetByteArrayElements(ENVPAR buf, &isCopy2);
+        if (buffP == NULL) {
+            h5JNIFatalError(env, "H5Dfill:  buf not pinned");
         } /* end if */
-    } /* end if */
-    else
-        fillP = NULL;
+        else {
+            if(fill) {
+                fillP = ENVPTR->GetByteArrayElements(ENVPAR fill, &isCopy1);
+                if (fillP == NULL) {
+                    ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, JNI_ABORT);
+                    h5JNIFatalError( env, "H5Dfill:  fill not pinned");
+                    return;
+                } /* end if */
+            } /* end if */
+            else
+                fillP = NULL;
 
-    status = H5Dfill((const void*)fillP, (hid_t)fill_type_id, (void*)buffP, (hid_t)buf_type_id, (hid_t)space_id);
-    if(fillP) {
-        /* free the buffer without copying back */
-        /* end if */ ENVPTR->ReleaseByteArrayElements(ENVPAR fill, fillP, JNI_ABORT);
+            status = H5Dfill((const void*)fillP, (hid_t)fill_type_id, (void*)buffP, (hid_t)buf_type_id, (hid_t)space_id);
+            if(fillP) {
+                /* free the buffer without copying back */
+                ENVPTR->ReleaseByteArrayElements(ENVPAR fill, fillP, JNI_ABORT);
+            } /* end if */
+            if (status < 0) {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, JNI_ABORT);
+                h5libraryError(env);
+            } /* end if */
+            else {
+                if (isCopy2 == JNI_TRUE) {
+                    ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, 0);
+                } /* end if */
+            } /* end else */
+        }
     }
-    if (status < 0) {
-        ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, JNI_ABORT);
-        h5libraryError(env);
-    } /* end if */
-    else {
-        if (isCopy2 == JNI_TRUE) {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, 0);
-        } /* end if */
-    } /* end else */
 } /* end Java_hdf_hdf5lib_H5_H5Dfill */
 
 /*
@@ -1638,35 +1643,35 @@ Java_hdf_hdf5lib_H5_H5Dset_1extent
 
     if (buf == NULL) {
         h5nullArgument(env, "H5Dset_extent:  buf is NULL");
-        return;
-    } /* end if */
-
-    rank = ENVPTR->GetArrayLength(ENVPAR buf);
-    if (rank <= 0) {
-        h5JNIFatalError(env, "H5Dset_extent:  rank <=0");
     } /* end if */
     else {
-        buffP = ENVPTR->GetLongArrayElements(ENVPAR buf, &isCopy);
-        if (buffP == NULL) {
-            h5JNIFatalError( env, "H5Dset_extent:  buf not pinned");
+        rank = ENVPTR->GetArrayLength(ENVPAR buf);
+        if (rank <= 0) {
+            h5JNIFatalError(env, "H5Dset_extent:  rank <=0");
         } /* end if */
         else {
-            dims = (hsize_t*)HDmalloc((size_t)rank * sizeof(hsize_t));
-            for (i = 0; i< rank; i++)
-                dims[i] = (hsize_t)buffP[i];
+            buffP = ENVPTR->GetLongArrayElements(ENVPAR buf, &isCopy);
+            if (buffP == NULL) {
+                h5JNIFatalError( env, "H5Dset_extent:  buf not pinned");
+            } /* end if */
+            else {
+                dims = (hsize_t*)HDmalloc((size_t)rank * sizeof(hsize_t));
+                for (i = 0; i< rank; i++)
+                    dims[i] = (hsize_t)buffP[i];
 
-            status = H5Dset_extent((hid_t)loc_id, (hsize_t*)dims);
+                status = H5Dset_extent((hid_t)loc_id, (hsize_t*)dims);
 
-            HDfree (dims);
+                HDfree (dims);
 
-            /* free the buffer without copying back */
-            ENVPTR->ReleaseLongArrayElements(ENVPAR buf, buffP, JNI_ABORT);
+                /* free the buffer without copying back */
+                ENVPTR->ReleaseLongArrayElements(ENVPAR buf, buffP, JNI_ABORT);
 
-            if (status < 0) {
-                h5libraryError(env);
-            } /* end if */
+                if (status < 0) {
+                    h5libraryError(env);
+                } /* end if */
+            } /* end else */
         } /* end else */
-    } /* end else */
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Dset_1extent */
 
 static herr_t
@@ -1747,34 +1752,32 @@ Java_hdf_hdf5lib_H5_H5Diterate
 
     if (op_data == NULL) {
         h5nullArgument(env,  "H5Diterate:  op_data is NULL");
-        return -1;
     } /* end if */
-    if (callback_op == NULL) {
+    else if (callback_op == NULL) {
         h5nullArgument(env,  "H5Diterate:  callback_op is NULL");
-        return -1;
     } /* end if */
-
-    if (buf == NULL) {
+    else if (buf == NULL) {
         h5nullArgument(env,  "H5Diterate:  buf is NULL");
-        return -1;
-    } /* end if */
-    buffP = ENVPTR->GetByteArrayElements(ENVPAR buf, &isCopy);
-    if (buffP == NULL) {
-        h5JNIFatalError(env, "H5Diterate:  buf not pinned");
     } /* end if */
     else {
-        status = H5Diterate((void*)buffP, (hid_t)buf_type, (hid_t)space, (H5D_operator_t)H5D_iterate_cb, (void*)op_data);
-
-        if (status < 0) {
-        ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, JNI_ABORT);
-        h5libraryError(env);
+        buffP = ENVPTR->GetByteArrayElements(ENVPAR buf, &isCopy);
+        if (buffP == NULL) {
+            h5JNIFatalError(env, "H5Diterate:  buf not pinned");
         } /* end if */
         else {
-            if (isCopy == JNI_TRUE) {
-                ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, 0);
+            status = H5Diterate((void*)buffP, (hid_t)buf_type, (hid_t)space, (H5D_operator_t)H5D_iterate_cb, (void*)op_data);
+
+            if (status < 0) {
+            ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, JNI_ABORT);
+            h5libraryError(env);
             } /* end if */
+            else {
+                if (isCopy == JNI_TRUE) {
+                    ENVPTR->ReleaseByteArrayElements(ENVPAR buf, buffP, 0);
+                } /* end if */
+            } /* end else */
         } /* end else */
-    } /* end else */
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Diterate */
diff --git a/java/src/jni/h5eImp.c b/java/src/jni/h5eImp.c
index 84cbacd..6e05515 100644
--- a/java/src/jni/h5eImp.c
+++ b/java/src/jni/h5eImp.c
@@ -98,14 +98,15 @@ Java_hdf_hdf5lib_H5_H5Eregister_1class
     const char* the_lib_name;
     const char* the_version;
 
-    PIN_JAVA_STRING_THREE(cls_name, the_cls_name, lib_name, the_lib_name, version, the_version, -1);
+    PIN_JAVA_STRING_THREE(cls_name, the_cls_name, lib_name, the_lib_name, version, the_version);
+    if (the_cls_name != NULL && the_lib_name != NULL && the_version != NULL) {
+        ret_val = H5Eregister_class(the_cls_name, the_lib_name, the_version);
 
-    ret_val = H5Eregister_class(the_cls_name, the_lib_name, the_version);
+        UNPIN_JAVA_STRING_THREE(cls_name, the_cls_name, lib_name, the_lib_name, version, the_version);
 
-    UNPIN_JAVA_STRING_THREE(cls_name, the_cls_name, lib_name, the_lib_name, version, the_version);
-
-    if (ret_val < 0)
-        h5libraryError(env);
+        if (ret_val < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)ret_val;
 } /* end Java_hdf_hdf5lib_H5_H5Eregister_1class */
@@ -159,14 +160,15 @@ Java_hdf_hdf5lib_H5_H5Ecreate_1msg
         h5badArgument(env, "H5Ecreate_msg: invalid argument");
     } /* end if */
     else {
-        PIN_JAVA_STRING(err_msg, the_err_msg, -1);
-
-        ret_val = H5Ecreate_msg((hid_t)err_id, error_msg_type, the_err_msg);
+        PIN_JAVA_STRING(err_msg, the_err_msg);
+        if (the_err_msg != NULL) {
+            ret_val = H5Ecreate_msg((hid_t)err_id, error_msg_type, the_err_msg);
 
-        UNPIN_JAVA_STRING(err_msg, the_err_msg);
+            UNPIN_JAVA_STRING(err_msg, the_err_msg);
 
-        if (ret_val < 0)
-            h5libraryError(env);
+            if (ret_val < 0)
+                h5libraryError(env);
+        }
     } /* end else */
 
     return (jlong)ret_val;
@@ -305,7 +307,7 @@ Java_hdf_hdf5lib_H5_H5Eget_1class_1name
  */
 JNIEXPORT void JNICALL
 Java_hdf_hdf5lib_H5_H5Eset_1current_1stack
-	(JNIEnv *env, jclass cls, jlong stk_id)
+    (JNIEnv *env, jclass cls, jlong stk_id)
 {
     if (stk_id < 0) {
         h5badArgument(env, "H5Eset_current_stack: invalid argument");
@@ -358,15 +360,16 @@ Java_hdf_hdf5lib_H5_H5Epush2
         h5badArgument(env, "H5Epush: invalid minor_id argument");
     } /* end else if */
     else {
-        PIN_JAVA_STRING_THREE0(filename, fName, funcname, fncName, err_desc, errMsg);
+        PIN_JAVA_STRING_THREE(filename, fName, funcname, fncName, err_desc, errMsg);
+        if (fName != NULL && fncName != NULL && errMsg != NULL) {
+            ret_val = H5Epush2((hid_t)stk_id, fName, fncName, (unsigned)linenumber, (hid_t)class_id,
+                    (hid_t)major_id, (hid_t)minor_id, errMsg);
 
-        ret_val = H5Epush2((hid_t)stk_id, fName, fncName, (unsigned)linenumber, (hid_t)class_id,
-                (hid_t)major_id, (hid_t)minor_id, errMsg);
+            UNPIN_JAVA_STRING_THREE(filename, fName, funcname, fncName, err_desc, errMsg);
 
-        UNPIN_JAVA_STRING_THREE(filename, fName, funcname, fncName, err_desc, errMsg);
-
-        if (ret_val < 0)
-            h5libraryError(env);
+            if (ret_val < 0)
+                h5libraryError(env);
+        }
     } /* end else */
 } /* end Java_hdf_hdf5lib_H5_H5Epush2 */
 
diff --git a/java/src/jni/h5fImp.c b/java/src/jni/h5fImp.c
index 33a5932..5862ae7 100644
--- a/java/src/jni/h5fImp.c
+++ b/java/src/jni/h5fImp.c
@@ -45,14 +45,15 @@ Java_hdf_hdf5lib_H5__1H5Fopen
     hid_t       status = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        status = H5Fopen(fileName, (unsigned)flags, (hid_t)access_id );
 
-    status = H5Fopen(fileName, (unsigned)flags, (hid_t)access_id );
+        UNPIN_JAVA_STRING(name, fileName);
 
-    UNPIN_JAVA_STRING(name, fileName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)status;
 } /* end Java_hdf_hdf5lib_H5__1H5Fopen */
@@ -69,14 +70,15 @@ Java_hdf_hdf5lib_H5__1H5Fcreate
     hid_t       status = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        status = H5Fcreate(fileName, (unsigned)flags, create_id, access_id);
 
-    status = H5Fcreate(fileName, (unsigned)flags, create_id, access_id);
+        UNPIN_JAVA_STRING(name, fileName);
 
-    UNPIN_JAVA_STRING(name, fileName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)status;
 } /* end Java_hdf_hdf5lib_H5__1H5Fcreate */
@@ -152,16 +154,17 @@ Java_hdf_hdf5lib_H5_H5Fis_1hdf5
     htri_t      bval = JNI_FALSE;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, JNI_FALSE);
-
-    bval = H5Fis_hdf5(fileName);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        bval = H5Fis_hdf5(fileName);
 
-    UNPIN_JAVA_STRING(name, fileName);
+        UNPIN_JAVA_STRING(name, fileName);
 
-    if (bval > 0)
-        bval = JNI_TRUE;
-    else if (bval < 0)
-        h5libraryError(env);
+        if (bval > 0)
+            bval = JNI_TRUE;
+        else if (bval < 0)
+            h5libraryError(env);
+    }
 
     return (jboolean)bval;
 } /* end Java_hdf_hdf5lib_H5_H5Fis_1hdf5 */
@@ -251,14 +254,15 @@ Java_hdf_hdf5lib_H5_H5Fmount
     herr_t      status = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
-
-    status = H5Fmount((hid_t)loc_id, fileName, (hid_t)child_id, (hid_t)plist_id);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        status = H5Fmount((hid_t)loc_id, fileName, (hid_t)child_id, (hid_t)plist_id);
 
-    UNPIN_JAVA_STRING(name, fileName);
+        UNPIN_JAVA_STRING(name, fileName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Fmount */
@@ -275,14 +279,15 @@ Java_hdf_hdf5lib_H5_H5Funmount
     herr_t      status = -1;
     const char *fileName;
 
-    PIN_JAVA_STRING(name, fileName, -1);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        status = H5Funmount((hid_t)loc_id, fileName);
 
-    status = H5Funmount((hid_t)loc_id, fileName);
+        UNPIN_JAVA_STRING(name, fileName);
 
-    UNPIN_JAVA_STRING(name, fileName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Funmount */
diff --git a/java/src/jni/h5gImp.c b/java/src/jni/h5gImp.c
index a2c0de0..c40ed64 100644
--- a/java/src/jni/h5gImp.c
+++ b/java/src/jni/h5gImp.c
@@ -69,33 +69,30 @@ create_H5G_info_t
     jclass   cls;
     jboolean jmounted;
     jint     storage_type;
-    jobject  obj;
+    jobject  obj = NULL;
     jfieldID fid_storage_type, fid_nlinks, fid_max_corder, fid_mounted;
 
     cls = ENVPTR->FindClass(ENVPAR "hdf/hdf5lib/structs/H5G_info_t");
-    if (cls == NULL)
-        return NULL;
-
-    obj = ENVPTR->AllocObject(ENVPAR cls);
-    if (obj == NULL)
-        return NULL;
-
-    fid_storage_type = ENVPTR->GetFieldID(ENVPAR cls, "storage_type", "I");
-    fid_nlinks = ENVPTR->GetFieldID(ENVPAR cls, "nlinks", "J");
-    fid_max_corder = ENVPTR->GetFieldID(ENVPAR cls, "max_corder", "J");
-    fid_mounted = ENVPTR->GetFieldID(ENVPAR cls, "mounted", "Z");
-
-    if (fid_storage_type==NULL || fid_nlinks==NULL || fid_max_corder==NULL || fid_mounted == NULL)
-        return NULL;
-
-    jmounted = (group_info.mounted==0) ? JNI_FALSE : JNI_TRUE;
-    storage_type = (jint)group_info.storage_type;
-
-    ENVPTR->SetIntField(ENVPAR obj, fid_storage_type, (jint)storage_type);
-    ENVPTR->SetLongField(ENVPAR obj, fid_nlinks, (jlong)group_info.nlinks);
-    ENVPTR->SetLongField(ENVPAR obj, fid_max_corder, (jlong)group_info.max_corder);
-    ENVPTR->SetBooleanField(ENVPAR obj, fid_mounted, jmounted);
-
+    if (cls != NULL) {
+        obj = ENVPTR->AllocObject(ENVPAR cls);
+        if (obj != NULL) {
+            if ((fid_storage_type = ENVPTR->GetFieldID(ENVPAR cls, "storage_type", "I")) != NULL) {
+                if ((fid_nlinks = ENVPTR->GetFieldID(ENVPAR cls, "nlinks", "J")) != NULL) {
+                    if ((fid_max_corder = ENVPTR->GetFieldID(ENVPAR cls, "max_corder", "J")) != NULL) {
+                        if ((fid_mounted = ENVPTR->GetFieldID(ENVPAR cls, "mounted", "Z")) != NULL) {
+                            jmounted = (group_info.mounted==0) ? JNI_FALSE : JNI_TRUE;
+                            storage_type = (jint)group_info.storage_type;
+
+                            ENVPTR->SetIntField(ENVPAR obj, fid_storage_type, (jint)storage_type);
+                            ENVPTR->SetLongField(ENVPAR obj, fid_nlinks, (jlong)group_info.nlinks);
+                            ENVPTR->SetLongField(ENVPAR obj, fid_max_corder, (jlong)group_info.max_corder);
+                            ENVPTR->SetBooleanField(ENVPAR obj, fid_mounted, jmounted);
+                        }
+                    }
+                }
+            }
+        }
+    }
     return obj;
 } /* end create_H5G_info_t */
 
@@ -112,13 +109,14 @@ Java_hdf_hdf5lib_H5__1H5Gcreate2
     hid_t       group_id = -1;
     const char *gName;
 
-    PIN_JAVA_STRING(name, gName, -1);
+    PIN_JAVA_STRING(name, gName);
+    if (gName != NULL) {
+        group_id = H5Gcreate2((hid_t)loc_id, gName, (hid_t)link_plist_id, (hid_t)create_plist_id, (hid_t)access_plist_id );
 
-    group_id = H5Gcreate2((hid_t)loc_id, gName, (hid_t)link_plist_id, (hid_t)create_plist_id, (hid_t)access_plist_id );
-
-    UNPIN_JAVA_STRING(name, gName);
-    if (group_id < 0)
-        h5libraryError(env);
+        UNPIN_JAVA_STRING(name, gName);
+        if (group_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)group_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Gcreate2 */
@@ -153,14 +151,15 @@ Java_hdf_hdf5lib_H5__1H5Gopen2
     hid_t group_id = -1;
     const char *gName;
 
-    PIN_JAVA_STRING(name, gName, -1);
+    PIN_JAVA_STRING(name, gName);
+    if (gName != NULL) {
+        group_id = H5Gopen2((hid_t)loc_id, gName, (hid_t)access_plist_id );
 
-    group_id = H5Gopen2((hid_t)loc_id, gName, (hid_t)access_plist_id );
+        UNPIN_JAVA_STRING(name, gName);
 
-    UNPIN_JAVA_STRING(name, gName);
-
-    if (group_id < 0)
-        h5libraryError(env);
+        if (group_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)group_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Gopen2 */
@@ -192,14 +191,15 @@ JNIEXPORT jobject JNICALL
 Java_hdf_hdf5lib_H5_H5Gget_1info
     (JNIEnv *env, jclass cls, jlong loc_id)
 {
+    jobject    obj = NULL;
     H5G_info_t group_info;
 
-    if (H5Gget_info((hid_t)loc_id, &group_info) < 0) {
+    if (H5Gget_info((hid_t)loc_id, &group_info) < 0)
         h5libraryError(env);
-        return NULL;
-    } /* end if */
+    else
+        obj = create_H5G_info_t(env, group_info);
 
-    return create_H5G_info_t(env, group_info);
+    return obj;
 } /* end Java_hdf_hdf5lib_H5_H5Gget_1info */
 
 /*
@@ -211,22 +211,24 @@ JNIEXPORT jobject JNICALL
 Java_hdf_hdf5lib_H5_H5Gget_1info_1by_1name
     (JNIEnv *env, jclass cls, jlong loc_id, jstring name, jlong lapl_id)
 {
+    jobject     obj = NULL;
     herr_t      ret_val = -1;
     const char *gName;
     H5G_info_t  group_info;
 
-    PIN_JAVA_STRING(name, gName, NULL);
+    PIN_JAVA_STRING(name, gName);
+    if (gName != NULL) {
+        ret_val = H5Gget_info_by_name((hid_t)loc_id, gName, &group_info, (hid_t)lapl_id);
 
-    ret_val = H5Gget_info_by_name((hid_t)loc_id, gName, &group_info, (hid_t)lapl_id);
+        UNPIN_JAVA_STRING(name, gName);
 
-    UNPIN_JAVA_STRING(name, gName);
-
-    if (ret_val < 0) {
-        h5libraryError(env);
-        return NULL;
-    } /* end if */
+        if (ret_val < 0)
+            h5libraryError(env);
+        else
+            obj = create_H5G_info_t(env, group_info);
+    }
 
-    return create_H5G_info_t(env, group_info);
+    return obj;
 } /* end Java_hdf_hdf5lib_H5_H5Gget_1info_1by_1name */
 
 /*
@@ -239,25 +241,27 @@ Java_hdf_hdf5lib_H5_H5Gget_1info_1by_1idx
     (JNIEnv *env, jclass cls, jlong loc_id, jstring name, jint index_type,
           jint order, jlong n, jlong lapl_id)
 {
+    jobject         obj = NULL;
     herr_t          ret_val = -1;
     const char     *gName;
     H5G_info_t      group_info;
     H5_index_t      cindex_type = (H5_index_t)index_type;
     H5_iter_order_t corder = (H5_iter_order_t)order;
 
-    PIN_JAVA_STRING(name, gName, NULL);
-
-    ret_val = H5Gget_info_by_idx((hid_t)loc_id, gName, cindex_type,
-            corder, (hsize_t)n, &group_info, (hid_t)lapl_id);
+    PIN_JAVA_STRING(name, gName);
+    if (gName != NULL) {
+        ret_val = H5Gget_info_by_idx((hid_t)loc_id, gName, cindex_type,
+                corder, (hsize_t)n, &group_info, (hid_t)lapl_id);
 
-    UNPIN_JAVA_STRING(name, gName);
+        UNPIN_JAVA_STRING(name, gName);
 
-    if (ret_val < 0) {
-        h5libraryError(env);
-        return NULL;
-    } /* end if */
+        if (ret_val < 0)
+            h5libraryError(env);
+        else
+            obj = create_H5G_info_t(env, group_info);
+    }
 
-    return create_H5G_info_t(env, group_info);
+    return obj;
 } /* end Java_hdf_hdf5lib_H5_H5Gget_1info_1by_1idx */
 
 /*
@@ -267,7 +271,7 @@ Java_hdf_hdf5lib_H5_H5Gget_1info_1by_1idx
  */
 JNIEXPORT void JNICALL
 Java_hdf_hdf5lib_H5_H5Gflush
-	(JNIEnv *env, jclass clss, jlong loc_id)
+    (JNIEnv *env, jclass clss, jlong loc_id)
 {
     if (H5Gflush((hid_t)loc_id) < 0)
         h5libraryError(env);
@@ -280,7 +284,7 @@ Java_hdf_hdf5lib_H5_H5Gflush
  */
 JNIEXPORT void JNICALL
 Java_hdf_hdf5lib_H5_H5Grefresh
-	(JNIEnv *env, jclass clss, jlong loc_id)
+    (JNIEnv *env, jclass clss, jlong loc_id)
 {
     if (H5Grefresh((hid_t)loc_id) < 0)
         h5libraryError(env);
diff --git a/java/src/jni/h5iImp.c b/java/src/jni/h5iImp.c
index 9fce3ef..d2f845a 100644
--- a/java/src/jni/h5iImp.c
+++ b/java/src/jni/h5iImp.c
@@ -91,6 +91,45 @@ Java_hdf_hdf5lib_H5_H5Iget_1name
 
 /*
  * Class:     hdf_hdf5lib_H5
+ * Method:    H5Iget_name_str
+ * Signature: (J)Ljava/lang/String;
+ */
+JNIEXPORT jstring JNICALL
+Java_hdf_hdf5lib_H5_H5Iget_1name_1str
+    (JNIEnv *env, jclass clss, jlong obj_id)
+{
+    char *aName;
+    jstring  str = NULL;
+    ssize_t  buf_size;
+
+    /* get the length of the name */
+    buf_size = H5Iget_name((hid_t)obj_id, NULL, 0);
+
+    if (buf_size <= 0) {
+        h5badArgument(env, "H5Iget_name:  buf_size <= 0");
+    } /* end if */
+    else {
+        buf_size++; /* add extra space for the null terminator */
+        aName = (char*)HDmalloc(sizeof(char) * (size_t)buf_size);
+        if (aName == NULL) {
+            h5outOfMemory(env, "H5Iget_name:  malloc failed");
+        } /* end if */
+        else {
+            buf_size = H5Iget_name((hid_t)obj_id, aName, (size_t)buf_size);
+            if (buf_size < 0) {
+                h5libraryError(env);
+            } /* end if */
+            else {
+                str = ENVPTR->NewStringUTF(ENVPAR aName);
+            }
+            HDfree(aName);
+        }
+    }
+    return str;
+} /* end Java_hdf_hdf5lib_H5_H5Iget_1name */
+
+/*
+ * Class:     hdf_hdf5lib_H5
  * Method:    H5Iget_ref
  * Signature: (J)I
  */
diff --git a/java/src/jni/h5iImp.h b/java/src/jni/h5iImp.h
index f7472b8..f6fe56b 100644
--- a/java/src/jni/h5iImp.h
+++ b/java/src/jni/h5iImp.h
@@ -43,6 +43,15 @@ Java_hdf_hdf5lib_H5_H5Iget_1name
 
 /*
  * Class:     hdf_hdf5lib_H5
+ * Method:    H5Iget_name_str
+ * Signature: (J)Ljava/lang/String;
+ */
+JNIEXPORT jstring JNICALL
+Java_hdf_hdf5lib_H5_H5Iget_1name_1str
+  (JNIEnv*, jclass, jlong);
+
+/*
+ * Class:     hdf_hdf5lib_H5
  * Method:    H5Iget_ref
  * Signature: (J)I
  */
diff --git a/java/src/jni/h5jni.h b/java/src/jni/h5jni.h
index da49eeb..9414d31 100644
--- a/java/src/jni/h5jni.h
+++ b/java/src/jni/h5jni.h
@@ -67,29 +67,17 @@
 
 
 /* Macros for string access */
-#define PIN_JAVA_STRING(javastr,localstr,retdefault) {                           \
+#define PIN_JAVA_STRING(javastr,localstr) {                                     \
     jboolean isCopy;                                                             \
+    (localstr) = NULL;                                                      \
     if ((javastr) == NULL) {                                                     \
         h5nullArgument(env, "java string is NULL");                              \
-        return (retdefault);                                                     \
     }                                                                            \
-    (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
-    if ((localstr) == NULL) {                                                    \
-        h5JNIFatalError(env, "local c string is not pinned");                    \
-        return (retdefault);                                                     \
-    }                                                                            \
-}
-
-#define PIN_JAVA_STRING0(javastr,localstr) {                                     \
-    jboolean isCopy;                                                             \
-    if ((javastr) == NULL) {                                                     \
-        h5nullArgument(env, "java string is NULL");                              \
-        return;                                                                  \
-    }                                                                            \
-    (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
-    if ((localstr) == NULL) {                                                    \
-        h5JNIFatalError(env, "local c string is not pinned");                    \
-        return;                                                                  \
+    else {                                                                       \
+        (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
+        if ((localstr) == NULL) {                                                    \
+            h5JNIFatalError(env, "local c string is not pinned");                    \
+        }                                                                        \
     }                                                                            \
 }
 
@@ -97,49 +85,28 @@
      ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));                \
 }
 
-#define PIN_JAVA_STRING_TWO(javastr,localstr,java2str,local2str,retdefault) {    \
+#define PIN_JAVA_STRING_TWO(javastr,localstr,java2str,local2str) {              \
     jboolean isCopy;                                                             \
+    (localstr) = NULL;                                                      \
+    (local2str) = NULL;                                                      \
     if ((javastr) == NULL) {                                                     \
         h5nullArgument(env, "java string is NULL");                              \
-        return (retdefault);                                                     \
     }                                                                            \
-    if ((java2str) == NULL) {                                                    \
+    else if ((java2str) == NULL) {                                                    \
         h5nullArgument(env, "second java string is NULL");                       \
-        return (retdefault);                                                     \
     }                                                                            \
-    (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
-    if ((localstr) == NULL) {                                                    \
-        h5JNIFatalError(env, "local c string is not pinned");                    \
-        return (retdefault);                                                     \
-    }                                                                            \
-    (local2str) = ENVPTR->GetStringUTFChars(ENVPAR (java2str), &isCopy);         \
-    if ((local2str) == NULL) {                                                   \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
-        h5JNIFatalError(env, "second local c string is not pinned");             \
-        return (retdefault);                                                     \
-    }                                                                            \
-}
-
-#define PIN_JAVA_STRING_TWO0(javastr,localstr,java2str,local2str) {              \
-    jboolean isCopy;                                                             \
-    if ((javastr) == NULL) {                                                     \
-        h5nullArgument(env, "java string is NULL");                              \
-        return;                                                                  \
-    }                                                                            \
-    if ((java2str) == NULL) {                                                    \
-        h5nullArgument(env, "second java string is NULL");                       \
-        return;                                                                  \
-    }                                                                            \
-    (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
-    if ((localstr) == NULL) {                                                    \
-        h5JNIFatalError(env, "local c string is not pinned");                    \
-        return;                                                                  \
-    }                                                                            \
-    (local2str) = ENVPTR->GetStringUTFChars(ENVPAR (java2str), &isCopy);         \
-    if ((local2str) == NULL) {                                                   \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
-        h5JNIFatalError(env, "second local c string is not pinned");             \
-        return;                                                                  \
+    else {                                                                       \
+        (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
+        if ((localstr) == NULL) {                                                    \
+            h5JNIFatalError(env, "local c string is not pinned");                    \
+        }                                                                            \
+        else {                                                                   \
+            (local2str) = ENVPTR->GetStringUTFChars(ENVPAR (java2str), &isCopy);         \
+            if ((local2str) == NULL) {                                                   \
+                ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
+                h5JNIFatalError(env, "second local c string is not pinned");             \
+            }                                                                    \
+        }                                                                        \
     }                                                                            \
 }
 
@@ -148,71 +115,40 @@
      ENVPTR->ReleaseStringUTFChars(ENVPAR (java2str), (local2str));              \
 }
 
-#define PIN_JAVA_STRING_THREE(javastr,localstr,java2str,local2str,java3str,local3str,retdefault) {       \
-    jboolean isCopy;                                                             \
-    if ((javastr) == NULL) {                                                     \
-        h5nullArgument(env, "java string is NULL");                              \
-        return (retdefault);                                                     \
-    }                                                                            \
-    if ((java2str) == NULL) {                                                    \
-        h5nullArgument(env, "second java string is NULL");                       \
-        return (retdefault);                                                     \
-    }                                                                            \
-    if ((java3str) == NULL) {                                                    \
-        h5nullArgument(env, "third java string is NULL");                        \
-        return (retdefault);                                                     \
-    }                                                                            \
-    (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
-    if ((localstr) == NULL) {                                                    \
-        h5JNIFatalError(env, "local c string is not pinned");                    \
-        return (retdefault);                                                     \
-    }                                                                            \
-    (local2str) = ENVPTR->GetStringUTFChars(ENVPAR (java2str), &isCopy);         \
-    if ((local2str) == NULL) {                                                   \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
-        h5JNIFatalError(env, "second local c string is not pinned");             \
-        return (retdefault);                                                     \
-    }                                                                            \
-    (local3str) = ENVPTR->GetStringUTFChars(ENVPAR (java3str), &isCopy);         \
-    if ((local3str) == NULL) {                                                   \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (java2str), (local2str));           \
-        h5JNIFatalError(env, "third local c string is not pinned");              \
-        return (retdefault);                                                     \
-    }                                                                            \
-}
-
-#define PIN_JAVA_STRING_THREE0(javastr,localstr,java2str,local2str,java3str,local3str) {       \
+#define PIN_JAVA_STRING_THREE(javastr,localstr,java2str,local2str,java3str,local3str) {       \
     jboolean isCopy;                                                             \
+    (localstr) = NULL;                                                      \
+    (local2str) = NULL;                                                      \
+    (local3str) = NULL;                                                      \
     if ((javastr) == NULL) {                                                     \
         h5nullArgument(env, "java string is NULL");                              \
-        return;                                                                  \
     }                                                                            \
-    if ((java2str) == NULL) {                                                    \
+    else if ((java2str) == NULL) {                                                    \
         h5nullArgument(env, "second java string is NULL");                       \
-        return;                                                                  \
     }                                                                            \
-    if ((java3str) == NULL) {                                                    \
+    else if ((java3str) == NULL) {                                                    \
         h5nullArgument(env, "third java string is NULL");                        \
-        return;                                                                  \
-    }                                                                            \
-    (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
-    if ((localstr) == NULL) {                                                    \
-        h5JNIFatalError(env, "local c string is not pinned");                    \
-        return;                                                                  \
-    }                                                                            \
-    (local2str) = ENVPTR->GetStringUTFChars(ENVPAR (java2str), &isCopy);         \
-    if ((local2str) == NULL) {                                                   \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
-        h5JNIFatalError(env, "second local c string is not pinned");             \
-        return;                                                                  \
     }                                                                            \
-    (local3str) = ENVPTR->GetStringUTFChars(ENVPAR (java3str), &isCopy);         \
-    if ((local3str) == NULL) {                                                   \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
-        ENVPTR->ReleaseStringUTFChars(ENVPAR (java2str), (local2str));           \
-        h5JNIFatalError(env, "third local c string is not pinned");              \
-        return;                                                                  \
+    else {                                                                       \
+        (localstr) = ENVPTR->GetStringUTFChars(ENVPAR (javastr), &isCopy);           \
+        if ((localstr) == NULL) {                                                    \
+            h5JNIFatalError(env, "local c string is not pinned");                    \
+        }                                                                            \
+        else {                                                                   \
+            (local2str) = ENVPTR->GetStringUTFChars(ENVPAR (java2str), &isCopy);         \
+            if ((local2str) == NULL) {                                                   \
+                ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
+                h5JNIFatalError(env, "second local c string is not pinned");             \
+            }                                                                            \
+            else {                                                               \
+                (local3str) = ENVPTR->GetStringUTFChars(ENVPAR (java3str), &isCopy);         \
+                if ((local3str) == NULL) {                                                   \
+                    ENVPTR->ReleaseStringUTFChars(ENVPAR (javastr), (localstr));             \
+                    ENVPTR->ReleaseStringUTFChars(ENVPAR (java2str), (local2str));           \
+                    h5JNIFatalError(env, "third local c string is not pinned");              \
+                }                                                                \
+            }                                                                    \
+        }                                                                        \
     }                                                                            \
 }
 
diff --git a/java/src/jni/h5lImp.c b/java/src/jni/h5lImp.c
index eecb1cd..473b1c7 100644
--- a/java/src/jni/h5lImp.c
+++ b/java/src/jni/h5lImp.c
@@ -52,14 +52,15 @@ Java_hdf_hdf5lib_H5_H5Lcopy
     const char *lCurName;
     const char *lDstName;
 
-    PIN_JAVA_STRING_TWO0(cur_name, lCurName, dst_name, lDstName);
+    PIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
+    if (lCurName != NULL && lDstName != NULL) {
+        status = H5Lcopy((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
 
-    status = H5Lcopy((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
+        UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
 
-    UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Lcopy */
 
 /*
@@ -77,14 +78,15 @@ Java_hdf_hdf5lib_H5_H5Lcreate_1external
     const char *lCurName;
     const char *lDstName;
 
-    PIN_JAVA_STRING_THREE0(file_name, lFileName, cur_name, lCurName, dst_name, lDstName);
-
-    status = H5Lcreate_external(lFileName, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
+    PIN_JAVA_STRING_THREE(file_name, lFileName, cur_name, lCurName, dst_name, lDstName);
+    if (lFileName != NULL && lCurName != NULL && lDstName != NULL) {
+        status = H5Lcreate_external(lFileName, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING_THREE(file_name, lFileName, cur_name, lCurName, dst_name, lDstName);
+        UNPIN_JAVA_STRING_THREE(file_name, lFileName, cur_name, lCurName, dst_name, lDstName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Lcreate_1external */
 
 /*
@@ -101,14 +103,15 @@ Java_hdf_hdf5lib_H5_H5Lcreate_1hard
     const char *lCurName;
     const char *lDstName;
 
-    PIN_JAVA_STRING_TWO0(cur_name, lCurName, dst_name, lDstName);
+    PIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
+    if (lCurName != NULL && lDstName != NULL) {
+        status = H5Lcreate_hard((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
 
-    status = H5Lcreate_hard((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
+        UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
 
-    UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Lcreate_1hard */
 
 /*
@@ -125,14 +128,15 @@ Java_hdf_hdf5lib_H5_H5Lcreate_1soft
     const char *lCurName;
     const char *lDstName;
 
-    PIN_JAVA_STRING_TWO0(cur_name, lCurName, dst_name, lDstName);
-
-    status = H5Lcreate_soft(lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
+    PIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
+    if (lCurName != NULL && lDstName != NULL) {
+        status = H5Lcreate_soft(lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
+        UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Lcreate_1soft */
 
 /*
@@ -147,14 +151,15 @@ Java_hdf_hdf5lib_H5_H5Ldelete
     herr_t      status = -1;
     const char *lName;
 
-    PIN_JAVA_STRING0(name, lName);
-
-    status = H5Ldelete((hid_t)loc_id, lName, (hid_t)access_id);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        status = H5Ldelete((hid_t)loc_id, lName, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING(name, lName);
+        UNPIN_JAVA_STRING(name, lName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Ldelete */
 
 /*
@@ -171,14 +176,15 @@ Java_hdf_hdf5lib_H5_H5Ldelete_1by_1idx
     herr_t      status;
     const char *lName;
 
-    PIN_JAVA_STRING0(name, lName);
-
-    status = H5Ldelete_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, n, (hid_t)access_id);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        status = H5Ldelete_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, n, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING(name, lName);
+        UNPIN_JAVA_STRING(name, lName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Ldelete_1by_1idx */
 
 /*
@@ -193,16 +199,17 @@ Java_hdf_hdf5lib_H5_H5Lexists
     htri_t   bval = JNI_FALSE;
     const char *lName;
 
-    PIN_JAVA_STRING(name, lName, JNI_FALSE);
-
-    bval = H5Lexists((hid_t)loc_id, lName, (hid_t)access_id);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        bval = H5Lexists((hid_t)loc_id, lName, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING(name, lName);
+        UNPIN_JAVA_STRING(name, lName);
 
-    if (bval > 0)
-        bval = JNI_TRUE;
-    else if (bval < 0)
-        h5libraryError(env);
+        if (bval > 0)
+            bval = JNI_TRUE;
+        else if (bval < 0)
+            h5libraryError(env);
+    }
 
     return (jboolean)bval;
 } /* end Java_hdf_hdf5lib_H5_H5Lexists */
@@ -222,26 +229,27 @@ Java_hdf_hdf5lib_H5_H5Lget_1info
     H5L_info_t  infobuf;
     const char *lName;
 
-    PIN_JAVA_STRING(name, lName, NULL);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        status = H5Lget_info((hid_t)loc_id, lName, &infobuf, (hid_t)access_id);
 
-    status = H5Lget_info((hid_t)loc_id, lName, &infobuf, (hid_t)access_id);
-
-    UNPIN_JAVA_STRING(name, lName);
+        UNPIN_JAVA_STRING(name, lName);
 
-    if (status < 0) {
-        h5libraryError(env);
+        if (status < 0) {
+            h5libraryError(env);
+        } /* end if */
+        else {
+            args[0].i = infobuf.type;
+            args[1].z = infobuf.corder_valid;
+            args[2].j = infobuf.corder;
+            args[3].i = infobuf.cset;
+            if(infobuf.type==0)
+                args[4].j = (jlong)infobuf.u.address;
+            else
+                args[4].j = (jlong)infobuf.u.val_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5L_info_t", "(IZJIJ)V", args);
+        } /* end else */
     } /* end if */
-    else {
-        args[0].i = infobuf.type;
-        args[1].z = infobuf.corder_valid;
-        args[2].j = infobuf.corder;
-        args[3].i = infobuf.cset;
-        if(infobuf.type==0)
-            args[4].j = (jlong)infobuf.u.address;
-        else
-            args[4].j = (jlong)infobuf.u.val_size;
-        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5L_info_t", "(IZJIJ)V", args);
-    } /* end else */
     return ret_obj;
 } /* end Java_hdf_hdf5lib_H5_H5Lget_1info */
 
@@ -261,26 +269,27 @@ Java_hdf_hdf5lib_H5_H5Lget_1info_1by_1idx
     H5L_info_t  infobuf;
     const char *lName;
 
-    PIN_JAVA_STRING(name, lName, NULL);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        status = H5Lget_info_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, &infobuf, (hid_t)access_id);
 
-    status = H5Lget_info_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, &infobuf, (hid_t)access_id);
-
-    UNPIN_JAVA_STRING(name, lName);
+        UNPIN_JAVA_STRING(name, lName);
 
-    if (status < 0) {
-        h5libraryError(env);
-    } /* end if */
-    else {
-        args[0].i = infobuf.type;
-        args[1].z = infobuf.corder_valid;
-        args[2].j = infobuf.corder;
-        args[3].i = infobuf.cset;
-        if(infobuf.type==0)
-            args[4].j = (jlong)infobuf.u.address;
-        else
-            args[4].j = (jlong)infobuf.u.val_size;
-        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5L_info_t", "(IZJIJ)V", args);
-    } /* end els */
+        if (status < 0) {
+            h5libraryError(env);
+        } /* end if */
+        else {
+            args[0].i = infobuf.type;
+            args[1].z = infobuf.corder_valid;
+            args[2].j = infobuf.corder;
+            args[3].i = infobuf.cset;
+            if(infobuf.type==0)
+                args[4].j = (jlong)infobuf.u.address;
+            else
+                args[4].j = (jlong)infobuf.u.val_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5L_info_t", "(IZJIJ)V", args);
+        } /* end els */
+    }
     return ret_obj;
 } /* end Java_hdf_hdf5lib_H5_H5Lget_1info_1by_1idx */
 
@@ -289,7 +298,7 @@ Java_hdf_hdf5lib_H5_H5Lget_1info_1by_1idx
  * Method:    H5Lget_name_by_idx
  * Signature: (JLjava/lang/String;IIJJ)Ljava/lang/String;
  */
-JNIEXPORT jobject JNICALL
+JNIEXPORT jstring JNICALL
 Java_hdf_hdf5lib_H5_H5Lget_1name_1by_1idx
     (JNIEnv *env, jclass clss, jlong loc_id, jstring name,
         jint index_field, jint order, jlong link_n, jlong access_id)
@@ -300,39 +309,38 @@ Java_hdf_hdf5lib_H5_H5Lget_1name_1by_1idx
     const char *lName;
     char       *lValue;
 
-    PIN_JAVA_STRING(name, lName, NULL);
-
-    /* get the length of the link name */
-    status_size = H5Lget_name_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (char*)NULL, (size_t)0, H5P_DEFAULT);
-    if(status_size < 0) {
-        UNPIN_JAVA_STRING(name, lName);
-        h5libraryError(env);
-    } /* end if */
-    else {
-        buf_size = (size_t)status_size + 1;/* add extra space for the null terminator */
-
-        lValue = (char*)HDmalloc(sizeof(char) * buf_size);
-        if (lValue == NULL) {
-            UNPIN_JAVA_STRING(name, lName);
-            h5outOfMemory(env, "H5Lget_name_by_idx:  malloc failed ");
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        /* get the length of the link name */
+        status_size = H5Lget_name_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (char*)NULL, (size_t)0, H5P_DEFAULT);
+        if(status_size < 0) {
+            h5libraryError(env);
         } /* end if */
         else {
-            status_size = H5Lget_name_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (char*)lValue, (size_t)buf_size, (hid_t)access_id);
+            buf_size = (size_t)status_size + 1;/* add extra space for the null terminator */
 
-            UNPIN_JAVA_STRING(name, lName);
-
-            if (status_size < 0) {
-                HDfree(lValue);
-                h5libraryError(env);
+            lValue = (char*)HDmalloc(sizeof(char) * buf_size);
+            if (lValue == NULL) {
+                h5outOfMemory(env, "H5Lget_name_by_idx:  malloc failed ");
             } /* end if */
             else {
-                str = ENVPTR->NewStringUTF(ENVPAR lValue);
-                HDfree(lValue);
-                if (str == NULL)
-                    h5JNIFatalError(env, "H5Lget_name_by_idx:  return string not created");
+                status_size = H5Lget_name_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (char*)lValue, (size_t)buf_size, (hid_t)access_id);
+
+                if (status_size < 0) {
+                    HDfree(lValue);
+                    h5libraryError(env);
+                } /* end if */
+                else {
+                    str = ENVPTR->NewStringUTF(ENVPAR lValue);
+                    HDfree(lValue);
+                    if (str == NULL)
+                        h5JNIFatalError(env, "H5Lget_name_by_idx:  return string not created");
+                } /* end else */
             } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, lName);
+    }
+
     return str;
 } /* end Java_hdf_hdf5lib_H5_H5Lget_1name_1by_1idx */
 
@@ -354,79 +362,70 @@ Java_hdf_hdf5lib_H5_H5Lget_1value
     const char *obj_name;
     jstring     str;
 
-    PIN_JAVA_STRING(name, lName, -1);
-
     infobuf.type = -1;
-    /* get the length of the link val */
-    status = H5Lget_info((hid_t)loc_id, lName, &infobuf, H5P_DEFAULT);
-    if(status < 0) {
-        UNPIN_JAVA_STRING(name, lName);
-        h5libraryError(env);
-    } /* end if */
-    else {
-        buf_size = infobuf.u.val_size + 1;/* add extra space for the null terminator */
-
-        if(infobuf.type == H5L_TYPE_HARD) {
-            UNPIN_JAVA_STRING(name, lName);
-            h5JNIFatalError(env, "H5Lget_val:  link is hard type");
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        /* get the length of the link val */
+        status = H5Lget_info((hid_t)loc_id, lName, &infobuf, H5P_DEFAULT);
+        if(status < 0) {
+            h5libraryError(env);
         } /* end if */
         else {
-            lValue = (char*)HDmalloc(sizeof(char) * buf_size);
-            if (lValue == NULL) {
-                UNPIN_JAVA_STRING(name, lName);
-                h5outOfMemory(env, "H5Lget_val:  malloc failed");
+            buf_size = infobuf.u.val_size + 1;/* add extra space for the null terminator */
+
+            if(infobuf.type == H5L_TYPE_HARD) {
+                h5JNIFatalError(env, "H5Lget_val:  link is hard type");
             } /* end if */
             else {
-                status = H5Lget_val((hid_t)loc_id, lName, (void*)lValue, buf_size, (hid_t)access_id);
-
-                UNPIN_JAVA_STRING(name, lName);
-
-                if (status < 0) {
-                    HDfree(lValue);
-                    h5libraryError(env);
+                lValue = (char*)HDmalloc(sizeof(char) * buf_size);
+                if (lValue == NULL) {
+                    h5outOfMemory(env, "H5Lget_val:  malloc failed");
                 } /* end if */
-                else if(infobuf.type == H5L_TYPE_EXTERNAL) {
-                    status = H5Lunpack_elink_val(lValue, (size_t)infobuf.u.val_size, (unsigned*)NULL, &file_name, &obj_name);
+                else {
+                    status = H5Lget_val((hid_t)loc_id, lName, (void*)lValue, buf_size, (hid_t)access_id);
+
                     if (status < 0) {
-                        HDfree(lValue);
                         h5libraryError(env);
                     } /* end if */
-                    else {
-                        str = ENVPTR->NewStringUTF(ENVPAR obj_name);
-                        if (str == NULL) {
-                            HDfree(lValue);
-                            h5JNIFatalError(env, "H5Lget_val:  return string not created");
+                    else if(infobuf.type == H5L_TYPE_EXTERNAL) {
+                        status = H5Lunpack_elink_val(lValue, (size_t)infobuf.u.val_size, (unsigned*)NULL, &file_name, &obj_name);
+                        if (status < 0) {
+                            h5libraryError(env);
                         } /* end if */
                         else {
-                            ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
-
-                            str = ENVPTR->NewStringUTF(ENVPAR file_name);
+                            str = ENVPTR->NewStringUTF(ENVPAR obj_name);
                             if (str == NULL) {
-                                HDfree(lValue);
                                 h5JNIFatalError(env, "H5Lget_val:  return string not created");
                             } /* end if */
                             else {
-                                ENVPTR->SetObjectArrayElement(ENVPAR link_value, 1, str);
-                                HDfree(lValue);
+                                ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
+
+                                str = ENVPTR->NewStringUTF(ENVPAR file_name);
+                                if (str == NULL) {
+                                    h5JNIFatalError(env, "H5Lget_val:  return string not created");
+                                } /* end if */
+                                else {
+                                    ENVPTR->SetObjectArrayElement(ENVPAR link_value, 1, str);
+                                } /* end else */
                             } /* end else */
                         } /* end else */
-                    } /* end else */
-                } /* end else if */
-                else {
-                    str = ENVPTR->NewStringUTF(ENVPAR lValue);
-                    if (str == NULL) {
-                        /* exception -- fatal JNI error */
-                        HDfree(lValue);
-                        h5JNIFatalError(env, "H5Lget_val:  return string not created");
-                    } /* end if */
+                    } /* end else if */
                     else {
-                        ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
-                        HDfree(lValue);
+                        str = ENVPTR->NewStringUTF(ENVPAR lValue);
+                        if (str == NULL) {
+                            /* exception -- fatal JNI error */
+                            h5JNIFatalError(env, "H5Lget_val:  return string not created");
+                        } /* end if */
+                        else {
+                            ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
+                        } /* end else */
                     } /* end else */
+                    HDfree(lValue);
                 } /* end else */
             } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, lName);
+    }
 
     return infobuf.type;
 } /* end Java_hdf_hdf5lib_H5_H5Lget_1val */
@@ -450,80 +449,69 @@ Java_hdf_hdf5lib_H5_H5Lget_1value_1by_1idx
     const char *obj_name;
     jstring     str;
 
-    PIN_JAVA_STRING(name, lName, -1);
-
     infobuf.type = -1;
-    /* get the length of the link valuee */
-    status = H5Lget_info_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, &infobuf, (hid_t)access_id);
-    if(status < 0) {
-        UNPIN_JAVA_STRING(name, lName);
-        h5libraryError(env);
-        return -1;
-    } /* end if */
-    else {
-        buf_size = infobuf.u.val_size;
-        if(buf_size < 0) {
-            UNPIN_JAVA_STRING(name, lName);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        /* get the length of the link valuee */
+        status = H5Lget_info_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, &infobuf, (hid_t)access_id);
+        if(status < 0) {
             h5libraryError(env);
-            return -1;
         } /* end if */
         else {
-            lValue = (void*)HDmalloc(buf_size);
-            if (lValue == NULL) {
-                UNPIN_JAVA_STRING(name, lName);
-                h5outOfMemory(env, "H5Lget_val_by_idx:  malloc failed ");
-                return -1;
+            buf_size = infobuf.u.val_size;
+            if(buf_size < 0) {
+                h5libraryError(env);
             } /* end if */
             else {
-                status = H5Lget_val_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (void*)lValue, (size_t)buf_size, (hid_t)access_id);
-
-                UNPIN_JAVA_STRING(name, lName);
-
-                if (status < 0) {
-                    HDfree(lValue);
-                    h5libraryError(env);
+                lValue = (void*)HDmalloc(buf_size);
+                if (lValue == NULL) {
+                    h5outOfMemory(env, "H5Lget_val_by_idx:  malloc failed ");
                 } /* end if */
-                else if(infobuf.type == H5L_TYPE_EXTERNAL) {
-                    status = H5Lunpack_elink_val((char*)lValue, (size_t)infobuf.u.val_size, (unsigned*)NULL, (const char**)&file_name, (const char**)&obj_name);
+                else {
+                    status = H5Lget_val_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (void*)lValue, (size_t)buf_size, (hid_t)access_id);
+
                     if (status < 0) {
-                        HDfree(lValue);
                         h5libraryError(env);
                     } /* end if */
-                    else {
-                        str = ENVPTR->NewStringUTF(ENVPAR obj_name);
-                        if (str == NULL) {
-                            HDfree(lValue);
-                            h5JNIFatalError(env, "H5Lget_val_by_idx:  return string not created");
+                    else if(infobuf.type == H5L_TYPE_EXTERNAL) {
+                        status = H5Lunpack_elink_val((char*)lValue, (size_t)infobuf.u.val_size, (unsigned*)NULL, (const char**)&file_name, (const char**)&obj_name);
+                        if (status < 0) {
+                            h5libraryError(env);
                         } /* end if */
                         else {
-                            ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
-
-                            str = ENVPTR->NewStringUTF(ENVPAR file_name);
+                            str = ENVPTR->NewStringUTF(ENVPAR obj_name);
                             if (str == NULL) {
-                                HDfree(lValue);
                                 h5JNIFatalError(env, "H5Lget_val_by_idx:  return string not created");
                             } /* end if */
                             else {
-                                ENVPTR->SetObjectArrayElement(ENVPAR link_value, 1, str);
-                                HDfree(lValue);
+                                ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
+
+                                str = ENVPTR->NewStringUTF(ENVPAR file_name);
+                                if (str == NULL) {
+                                    h5JNIFatalError(env, "H5Lget_val_by_idx:  return string not created");
+                                } /* end if */
+                                else {
+                                    ENVPTR->SetObjectArrayElement(ENVPAR link_value, 1, str);
+                                } /* end else */
                             } /* end else */
                         } /* end else */
-                    } /* end else */
-                } /* end else if */
-                else {
-                    str = ENVPTR->NewStringUTF(ENVPAR (char *)lValue);
-                    if (str == NULL) {
-                        HDfree(lValue);
-                        h5JNIFatalError(env, "H5Lget_val_by_idx:  return string not created");
-                    } /* end if */
+                    } /* end else if */
                     else {
-                        ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
-                        HDfree(lValue);
+                        str = ENVPTR->NewStringUTF(ENVPAR (char *)lValue);
+                        if (str == NULL) {
+                            h5JNIFatalError(env, "H5Lget_val_by_idx:  return string not created");
+                        } /* end if */
+                        else {
+                            ENVPTR->SetObjectArrayElement(ENVPAR link_value, 0, str);
+                        } /* end else */
                     } /* end else */
+                    HDfree(lValue);
                 } /* end else */
             } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, lName);
+    }
+
     return infobuf.type;
 } /* end Java_hdf_hdf5lib_H5_H5Lget_1val_1by_1idx */
 
@@ -541,20 +529,21 @@ Java_hdf_hdf5lib_H5_H5Lmove
     const char *lCurName;
     const char *lDstName;
 
-    PIN_JAVA_STRING_TWO0(cur_name, lCurName, dst_name, lDstName);
+    PIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
+    if (lCurName != NULL && lDstName != NULL) {
+        status = H5Lmove((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
 
-    status = H5Lmove((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
+        UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
 
-    UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
 } /* end Java_hdf_hdf5lib_H5_H5Lmove */
 
 static herr_t
 H5L_iterate_cb
-    (hid_t g_id, const char *name, const H5L_info_t *info, void *op_data) 
+    (hid_t g_id, const char *name, const H5L_info_t *info, void *op_data)
 {
     JNIEnv    *cbenv;
     jint       status;
@@ -645,14 +634,15 @@ Java_hdf_hdf5lib_H5_H5Lvisit_1by_1name
         h5nullArgument(env,  "H5Lvisit_by_name:  op_data or callback_op is NULL");
     } /* end if */
     else {
-        PIN_JAVA_STRING(name, lName, -1);
-
-        status = H5Lvisit_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (H5L_iterate_t)H5L_iterate_cb, (void*)op_data, (hid_t)access_id);
+        PIN_JAVA_STRING(name, lName);
+        if (lName != NULL) {
+            status = H5Lvisit_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (H5L_iterate_t)H5L_iterate_cb, (void*)op_data, (hid_t)access_id);
 
-        UNPIN_JAVA_STRING(name, lName);
+            UNPIN_JAVA_STRING(name, lName);
 
-        if (status < 0)
-            h5libraryError(env);
+            if (status < 0)
+                h5libraryError(env);
+        }
     } /* end else */
 
     return status;
@@ -708,14 +698,15 @@ Java_hdf_hdf5lib_H5_H5Literate_1by_1name
         h5nullArgument(env,  "H5Literate_by_name:  op_data or callback_op is NULL");
     } /* end if */
     else {
-        PIN_JAVA_STRING(name, lName, -1);
+        PIN_JAVA_STRING(name, lName);
+        if (lName != NULL) {
+            status = H5Literate_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (hsize_t*)&start_idx, (H5L_iterate_t)H5L_iterate_cb, (void*)op_data, (hid_t)access_id);
 
-        status = H5Literate_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (hsize_t*)&start_idx, (H5L_iterate_t)H5L_iterate_cb, (void*)op_data, (hid_t)access_id);
-
-        UNPIN_JAVA_STRING(name, lName);
+            UNPIN_JAVA_STRING(name, lName);
 
-        if (status < 0)
-            h5libraryError(env);
+            if (status < 0)
+                h5libraryError(env);
+        }
     } /* end else */
 
     return status;
diff --git a/java/src/jni/h5lImp.h b/java/src/jni/h5lImp.h
index 93a187b..6b2f3e1 100644
--- a/java/src/jni/h5lImp.h
+++ b/java/src/jni/h5lImp.h
@@ -110,7 +110,7 @@ Java_hdf_hdf5lib_H5_H5Lget_1info_1by_1idx
  * Method:    H5Lget_name_by_idx
  * Signature: (JLjava/lang/String;IIJJ)Ljava/lang/String;
  */
-JNIEXPORT jobject JNICALL
+JNIEXPORT jstring JNICALL
 Java_hdf_hdf5lib_H5_H5Lget_1name_1by_1idx
 (JNIEnv*, jclass, jlong, jstring, jint, jint, jlong, jlong);
 
diff --git a/java/src/jni/h5oImp.c b/java/src/jni/h5oImp.c
index 872bb4c..24f6988 100644
--- a/java/src/jni/h5oImp.c
+++ b/java/src/jni/h5oImp.c
@@ -46,17 +46,18 @@ JNIEXPORT jlong JNICALL
 Java_hdf_hdf5lib_H5__1H5Oopen
     (JNIEnv *env, jclass clss, jlong loc_id, jstring name, jlong access_plist_id)
 {
-    hid_t       status;
+    hid_t       status = -1;
     const char *oName;
 
-    PIN_JAVA_STRING(name, oName, -1);
+    PIN_JAVA_STRING(name, oName);
+    if (oName != NULL) {
+        status = H5Oopen((hid_t)loc_id, oName, (hid_t)access_plist_id );
 
-    status = H5Oopen((hid_t)loc_id, oName, (hid_t)access_plist_id );
-
-    UNPIN_JAVA_STRING(name, oName);
+        UNPIN_JAVA_STRING(name, oName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)status;
 } /* end Java_hdf_hdf5lib_H5__1H5Oopen */
@@ -92,14 +93,15 @@ Java_hdf_hdf5lib_H5_H5Ocopy
     const char *lCurName;
     const char *lDstName;
 
-    PIN_JAVA_STRING_TWO0(cur_name, lCurName, dst_name, lDstName);
+    PIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
+    if (lCurName != NULL && lDstName != NULL) {
+        status = H5Ocopy((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
 
-    status = H5Ocopy((hid_t)cur_loc_id, lCurName, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
+        UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
 
-    UNPIN_JAVA_STRING_TWO(cur_name, lCurName, dst_name, lDstName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Ocopy */
 
 /*
@@ -123,44 +125,44 @@ Java_hdf_hdf5lib_H5_H5Oget_1info
 
     if (status < 0) {
         h5libraryError(env);
-        return NULL;
     } /* end if */
-
-    args[0].i = (jint)infobuf.hdr.version;
-    args[1].i = (jint)infobuf.hdr.nmesgs;
-    args[2].i = (jint)infobuf.hdr.nchunks;
-    args[3].i = (jint)infobuf.hdr.flags;
-    args[4].j = (jlong)infobuf.hdr.space.total;
-    args[5].j = (jlong)infobuf.hdr.space.meta;
-    args[6].j = (jlong)infobuf.hdr.space.mesg;
-    args[7].j = (jlong)infobuf.hdr.space.free;
-    args[8].j = (jlong)infobuf.hdr.mesg.present;
-    args[9].j = (jlong)infobuf.hdr.mesg.shared;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_hdr_info_t", "(IIIIJJJJJJ)V", args);
-    hdrinfobuf = ret_obj;
-
-    args[0].j = (jlong)infobuf.meta_size.obj.index_size;
-    args[1].j = (jlong)infobuf.meta_size.obj.heap_size;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
-    ihinfobuf1 = ret_obj;
-    args[0].j = (jlong)infobuf.meta_size.attr.index_size;
-    args[1].j = (jlong)infobuf.meta_size.attr.heap_size;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
-    ihinfobuf2 = ret_obj;
-
-    args[0].j = (jlong)infobuf.fileno;
-    args[1].j = (jlong)infobuf.addr;
-    args[2].i = infobuf.type;
-    args[3].i = (jint)infobuf.rc;
-    args[4].j = (jlong)infobuf.num_attrs;
-    args[5].j = infobuf.atime;
-    args[6].j = infobuf.mtime;
-    args[7].j = infobuf.ctime;
-    args[8].j = infobuf.btime;
-    args[9].l = hdrinfobuf;
-    args[10].l = ihinfobuf1;
-    args[11].l = ihinfobuf2;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_info_t", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V", args);
+    else {
+        args[0].i = (jint)infobuf.hdr.version;
+        args[1].i = (jint)infobuf.hdr.nmesgs;
+        args[2].i = (jint)infobuf.hdr.nchunks;
+        args[3].i = (jint)infobuf.hdr.flags;
+        args[4].j = (jlong)infobuf.hdr.space.total;
+        args[5].j = (jlong)infobuf.hdr.space.meta;
+        args[6].j = (jlong)infobuf.hdr.space.mesg;
+        args[7].j = (jlong)infobuf.hdr.space.free;
+        args[8].j = (jlong)infobuf.hdr.mesg.present;
+        args[9].j = (jlong)infobuf.hdr.mesg.shared;
+        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_hdr_info_t", "(IIIIJJJJJJ)V", args);
+        hdrinfobuf = ret_obj;
+
+        args[0].j = (jlong)infobuf.meta_size.obj.index_size;
+        args[1].j = (jlong)infobuf.meta_size.obj.heap_size;
+        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
+        ihinfobuf1 = ret_obj;
+        args[0].j = (jlong)infobuf.meta_size.attr.index_size;
+        args[1].j = (jlong)infobuf.meta_size.attr.heap_size;
+        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
+        ihinfobuf2 = ret_obj;
+
+        args[0].j = (jlong)infobuf.fileno;
+        args[1].j = (jlong)infobuf.addr;
+        args[2].i = infobuf.type;
+        args[3].i = (jint)infobuf.rc;
+        args[4].j = (jlong)infobuf.num_attrs;
+        args[5].j = infobuf.atime;
+        args[6].j = infobuf.mtime;
+        args[7].j = infobuf.ctime;
+        args[8].j = infobuf.btime;
+        args[9].l = hdrinfobuf;
+        args[10].l = ihinfobuf1;
+        args[11].l = ihinfobuf2;
+        CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_info_t", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V", args);
+    }
 
     return ret_obj;
 } /* end Java_hdf_hdf5lib_H5_H5Oget_1info */
@@ -183,52 +185,53 @@ Java_hdf_hdf5lib_H5_H5Oget_1info_1by_1name
     jobject     ihinfobuf2;
     jobject     ret_obj = NULL;
 
-    PIN_JAVA_STRING(name, lName, NULL);
-
-    status = H5Oget_info_by_name((hid_t)loc_id, lName, &infobuf, (hid_t)access_id);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        status = H5Oget_info_by_name((hid_t)loc_id, lName, &infobuf, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING(name, lName);
+        UNPIN_JAVA_STRING(name, lName);
 
-    if (status < 0) {
-        h5libraryError(env);
-        return NULL;
-    } /* end if */
-
-    args[0].i = (jint)infobuf.hdr.version;
-    args[1].i = (jint)infobuf.hdr.nmesgs;
-    args[2].i = (jint)infobuf.hdr.nchunks;
-    args[3].i = (jint)infobuf.hdr.flags;
-    args[4].j = (jlong)infobuf.hdr.space.total;
-    args[5].j = (jlong)infobuf.hdr.space.meta;
-    args[6].j = (jlong)infobuf.hdr.space.mesg;
-    args[7].j = (jlong)infobuf.hdr.space.free;
-    args[8].j = (jlong)infobuf.hdr.mesg.present;
-    args[9].j = (jlong)infobuf.hdr.mesg.shared;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_hdr_info_t", "(IIIIJJJJJJ)V", args);
-    hdrinfobuf = ret_obj;
-
-    args[0].j = (jlong)infobuf.meta_size.obj.index_size;
-    args[1].j = (jlong)infobuf.meta_size.obj.heap_size;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
-    ihinfobuf1 = ret_obj;
-    args[0].j = (jlong)infobuf.meta_size.attr.index_size;
-    args[1].j = (jlong)infobuf.meta_size.attr.heap_size;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
-    ihinfobuf2 = ret_obj;
-
-    args[0].j = (jlong)infobuf.fileno;
-    args[1].j = (jlong)infobuf.addr;
-    args[2].i = infobuf.type;
-    args[3].i = (jint)infobuf.rc;
-    args[4].j = (jlong)infobuf.num_attrs;
-    args[5].j = infobuf.atime;
-    args[6].j = infobuf.mtime;
-    args[7].j = infobuf.ctime;
-    args[8].j = infobuf.btime;
-    args[9].l = hdrinfobuf;
-    args[10].l = ihinfobuf1;
-    args[11].l = ihinfobuf2;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_info_t", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V", args);
+        if (status < 0) {
+            h5libraryError(env);
+        } /* end if */
+        else {
+            args[0].i = (jint)infobuf.hdr.version;
+            args[1].i = (jint)infobuf.hdr.nmesgs;
+            args[2].i = (jint)infobuf.hdr.nchunks;
+            args[3].i = (jint)infobuf.hdr.flags;
+            args[4].j = (jlong)infobuf.hdr.space.total;
+            args[5].j = (jlong)infobuf.hdr.space.meta;
+            args[6].j = (jlong)infobuf.hdr.space.mesg;
+            args[7].j = (jlong)infobuf.hdr.space.free;
+            args[8].j = (jlong)infobuf.hdr.mesg.present;
+            args[9].j = (jlong)infobuf.hdr.mesg.shared;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_hdr_info_t", "(IIIIJJJJJJ)V", args);
+            hdrinfobuf = ret_obj;
+
+            args[0].j = (jlong)infobuf.meta_size.obj.index_size;
+            args[1].j = (jlong)infobuf.meta_size.obj.heap_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
+            ihinfobuf1 = ret_obj;
+            args[0].j = (jlong)infobuf.meta_size.attr.index_size;
+            args[1].j = (jlong)infobuf.meta_size.attr.heap_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
+            ihinfobuf2 = ret_obj;
+
+            args[0].j = (jlong)infobuf.fileno;
+            args[1].j = (jlong)infobuf.addr;
+            args[2].i = infobuf.type;
+            args[3].i = (jint)infobuf.rc;
+            args[4].j = (jlong)infobuf.num_attrs;
+            args[5].j = infobuf.atime;
+            args[6].j = infobuf.mtime;
+            args[7].j = infobuf.ctime;
+            args[8].j = infobuf.btime;
+            args[9].l = hdrinfobuf;
+            args[10].l = ihinfobuf1;
+            args[11].l = ihinfobuf2;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_info_t", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V", args);
+        }
+    }
 
     return ret_obj;
 } /* end Java_hdf_hdf5lib_H5_H5Oget_1info_1by_1name */
@@ -252,52 +255,53 @@ Java_hdf_hdf5lib_H5_H5Oget_1info_1by_1idx
     jobject     ihinfobuf2;
     jobject     ret_obj = NULL;
 
-    PIN_JAVA_STRING(name, lName, NULL);
+    PIN_JAVA_STRING(name, lName);
+    if (lName != NULL) {
+        status = H5Oget_info_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, &infobuf, (hid_t)access_id);
 
-    status = H5Oget_info_by_idx((hid_t)loc_id, lName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, &infobuf, (hid_t)access_id);
+        UNPIN_JAVA_STRING(name, lName);
 
-    UNPIN_JAVA_STRING(name, lName);
-
-    if (status < 0) {
-        h5libraryError(env);
-        return NULL;
-    } /* end if */
-
-    args[0].i = (jint)infobuf.hdr.version;
-    args[1].i = (jint)infobuf.hdr.nmesgs;
-    args[2].i = (jint)infobuf.hdr.nchunks;
-    args[3].i = (jint)infobuf.hdr.flags;
-    args[4].j = (jlong)infobuf.hdr.space.total;
-    args[5].j = (jlong)infobuf.hdr.space.meta;
-    args[6].j = (jlong)infobuf.hdr.space.mesg;
-    args[7].j = (jlong)infobuf.hdr.space.free;
-    args[8].j = (jlong)infobuf.hdr.mesg.present;
-    args[9].j = (jlong)infobuf.hdr.mesg.shared;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_hdr_info_t", "(IIIIJJJJJJ)V", args);
-    hdrinfobuf = ret_obj;
-
-    args[0].j = (jlong)infobuf.meta_size.obj.index_size;
-    args[1].j = (jlong)infobuf.meta_size.obj.heap_size;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
-    ihinfobuf1 = ret_obj;
-    args[0].j = (jlong)infobuf.meta_size.attr.index_size;
-    args[1].j = (jlong)infobuf.meta_size.attr.heap_size;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
-    ihinfobuf2 = ret_obj;
-
-    args[0].j = (jlong)infobuf.fileno;
-    args[1].j = (jlong)infobuf.addr;
-    args[2].i = infobuf.type;
-    args[3].i = (jint)infobuf.rc;
-    args[4].j = (jlong)infobuf.num_attrs;
-    args[5].j = infobuf.atime;
-    args[6].j = infobuf.mtime;
-    args[7].j = infobuf.ctime;
-    args[8].j = infobuf.btime;
-    args[9].l = hdrinfobuf;
-    args[10].l = ihinfobuf1;
-    args[11].l = ihinfobuf2;
-    CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_info_t", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V", args);
+        if (status < 0) {
+            h5libraryError(env);
+        } /* end if */
+        else {
+            args[0].i = (jint)infobuf.hdr.version;
+            args[1].i = (jint)infobuf.hdr.nmesgs;
+            args[2].i = (jint)infobuf.hdr.nchunks;
+            args[3].i = (jint)infobuf.hdr.flags;
+            args[4].j = (jlong)infobuf.hdr.space.total;
+            args[5].j = (jlong)infobuf.hdr.space.meta;
+            args[6].j = (jlong)infobuf.hdr.space.mesg;
+            args[7].j = (jlong)infobuf.hdr.space.free;
+            args[8].j = (jlong)infobuf.hdr.mesg.present;
+            args[9].j = (jlong)infobuf.hdr.mesg.shared;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_hdr_info_t", "(IIIIJJJJJJ)V", args);
+            hdrinfobuf = ret_obj;
+
+            args[0].j = (jlong)infobuf.meta_size.obj.index_size;
+            args[1].j = (jlong)infobuf.meta_size.obj.heap_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
+            ihinfobuf1 = ret_obj;
+            args[0].j = (jlong)infobuf.meta_size.attr.index_size;
+            args[1].j = (jlong)infobuf.meta_size.attr.heap_size;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5_ih_info_t", "(JJ)V", args);
+            ihinfobuf2 = ret_obj;
+
+            args[0].j = (jlong)infobuf.fileno;
+            args[1].j = (jlong)infobuf.addr;
+            args[2].i = infobuf.type;
+            args[3].i = (jint)infobuf.rc;
+            args[4].j = (jlong)infobuf.num_attrs;
+            args[5].j = infobuf.atime;
+            args[6].j = infobuf.mtime;
+            args[7].j = infobuf.ctime;
+            args[8].j = infobuf.btime;
+            args[9].l = hdrinfobuf;
+            args[10].l = ihinfobuf1;
+            args[11].l = ihinfobuf2;
+            CALL_CONSTRUCTOR("hdf/hdf5lib/structs/H5O_info_t", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V", args);
+        }
+    }
 
     return ret_obj;
 } /* end Java_hdf_hdf5lib_H5_H5Oget_1info_1by_1idx */
@@ -315,14 +319,15 @@ Java_hdf_hdf5lib_H5_H5Olink
     herr_t      status = -1;
     const char *lDstName;
 
-    PIN_JAVA_STRING0(dst_name, lDstName);
-
-    status = H5Olink((hid_t)cur_loc_id, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
+    PIN_JAVA_STRING(dst_name, lDstName);
+    if (lDstName != NULL) {
+        status = H5Olink((hid_t)cur_loc_id, (hid_t)dst_loc_id, lDstName, (hid_t)create_id, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING(dst_name, lDstName);
+        UNPIN_JAVA_STRING(dst_name, lDstName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Olink */
 
 static herr_t
@@ -347,90 +352,71 @@ H5O_iterate_cb
         return -1;
     } /* end if */
     cls = CBENVPTR->GetObjectClass(CBENVPAR visit_callback);
-    if (cls == 0) {
-        /* printf("JNI H5O_iterate_cb error: GetObjectClass failed\n"); */
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-    mid = CBENVPTR->GetMethodID(CBENVPAR cls, "callback", "(JLjava/lang/String;Lhdf/hdf5lib/structs/H5O_info_t;Lhdf/hdf5lib/callbacks/H5O_iterate_t;)I");
-    if (mid == 0) {
-        /* printf("JNI H5O_iterate_cb error: GetMethodID failed\n"); */
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
+    if (cls != 0) {
+        mid = CBENVPTR->GetMethodID(CBENVPAR cls, "callback", "(JLjava/lang/String;Lhdf/hdf5lib/structs/H5O_info_t;Lhdf/hdf5lib/callbacks/H5O_iterate_t;)I");
+        if (mid != 0) {
+            str = CBENVPTR->NewStringUTF(CBENVPAR name);
+
+            args[0].i = (jint)info->hdr.version;
+            args[1].i = (jint)info->hdr.nmesgs;
+            args[2].i = (jint)info->hdr.nchunks;
+            args[3].i = (jint)info->hdr.flags;
+            args[4].j = (jlong)info->hdr.space.total;
+            args[5].j = (jlong)info->hdr.space.meta;
+            args[6].j = (jlong)info->hdr.space.mesg;
+            args[7].j = (jlong)info->hdr.space.free;
+            args[8].j = (jlong)info->hdr.mesg.present;
+            args[9].j = (jlong)info->hdr.mesg.shared;
+            // get a reference to the H5_hdr_info_t class
+            cls = CBENVPTR->FindClass(CBENVPAR "hdf/hdf5lib/structs/H5O_hdr_info_t");
+            if (cls != 0) {
+                // get a reference to the constructor; the name is <init>
+                constructor = CBENVPTR->GetMethodID(CBENVPAR cls, "<init>", "(IIIIJJJJJJ)V");
+                if (constructor != 0) {
+                    hdrinfobuf = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
+
+                    args[0].j = (jlong)info->meta_size.obj.index_size;
+                    args[1].j = (jlong)info->meta_size.obj.heap_size;
+                    // get a reference to the H5_ih_info_t class
+                    cls = CBENVPTR->FindClass(CBENVPAR "hdf/hdf5lib/structs/H5_ih_info_t");
+                    if (cls != 0) {
+                        // get a reference to the constructor; the name is <init>
+                        constructor = CBENVPTR->GetMethodID(CBENVPAR cls, "<init>", "(JJ)V");
+                        if (constructor != 0) {
+                            ihinfobuf1 = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
+                            args[0].j = (jlong)info->meta_size.attr.index_size;
+                            args[1].j = (jlong)info->meta_size.attr.heap_size;
+                            ihinfobuf2 = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
+
+                            args[0].j = (jlong)info->fileno;
+                            args[1].j = (jlong)info->addr;
+                            args[2].i = info->type;
+                            args[3].i = (jint)info->rc;
+                            args[4].j = (jlong)info->num_attrs;
+                            args[5].j = info->atime;
+                            args[6].j = info->mtime;
+                            args[7].j = info->ctime;
+                            args[8].j = info->btime;
+                            args[9].l = hdrinfobuf;
+                            args[10].l = ihinfobuf1;
+                            args[11].l = ihinfobuf2;
+                            // get a reference to the H5O_info_t class
+                            cls = CBENVPTR->FindClass(CBENVPAR "hdf/hdf5lib/structs/H5O_info_t");
+                            if (cls != 0) {
+                                // get a reference to the constructor; the name is <init>
+                                constructor = CBENVPTR->GetMethodID(CBENVPAR cls, "<init>", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V");
+                                if (constructor != 0) {
+                                    cb_info_t = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
+
+                                    status = CBENVPTR->CallIntMethod(CBENVPAR visit_callback, mid, g_id, str, cb_info_t, op_data);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
     } /* end if */
-    str = CBENVPTR->NewStringUTF(CBENVPAR name);
-
-    args[0].i = (jint)info->hdr.version;
-    args[1].i = (jint)info->hdr.nmesgs;
-    args[2].i = (jint)info->hdr.nchunks;
-    args[3].i = (jint)info->hdr.flags;
-    args[4].j = (jlong)info->hdr.space.total;
-    args[5].j = (jlong)info->hdr.space.meta;
-    args[6].j = (jlong)info->hdr.space.mesg;
-    args[7].j = (jlong)info->hdr.space.free;
-    args[8].j = (jlong)info->hdr.mesg.present;
-    args[9].j = (jlong)info->hdr.mesg.shared;
-    // get a reference to the H5_hdr_info_t class
-    cls = CBENVPTR->FindClass(CBENVPAR "hdf/hdf5lib/structs/H5O_hdr_info_t");
-    if (cls == 0) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-    // get a reference to the constructor; the name is <init>
-    constructor = CBENVPTR->GetMethodID(CBENVPAR cls, "<init>", "(IIIIJJJJJJ)V");
-    if (constructor == 0) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-    hdrinfobuf = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
-
-    args[0].j = (jlong)info->meta_size.obj.index_size;
-    args[1].j = (jlong)info->meta_size.obj.heap_size;
-    // get a reference to the H5_ih_info_t class
-    cls = CBENVPTR->FindClass(CBENVPAR "hdf/hdf5lib/structs/H5_ih_info_t");
-    if (cls == 0) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-    // get a reference to the constructor; the name is <init>
-    constructor = CBENVPTR->GetMethodID(CBENVPAR cls, "<init>", "(JJ)V");
-    if (constructor == 0) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-    ihinfobuf1 = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
-    args[0].j = (jlong)info->meta_size.attr.index_size;
-    args[1].j = (jlong)info->meta_size.attr.heap_size;
-    ihinfobuf2 = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
-
-    args[0].j = (jlong)info->fileno;
-    args[1].j = (jlong)info->addr;
-    args[2].i = info->type;
-    args[3].i = (jint)info->rc;
-    args[4].j = (jlong)info->num_attrs;
-    args[5].j = info->atime;
-    args[6].j = info->mtime;
-    args[7].j = info->ctime;
-    args[8].j = info->btime;
-    args[9].l = hdrinfobuf;
-    args[10].l = ihinfobuf1;
-    args[11].l = ihinfobuf2;
-    // get a reference to the H5O_info_t class
-    cls = CBENVPTR->FindClass(CBENVPAR "hdf/hdf5lib/structs/H5O_info_t");
-    if (cls == 0) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-    // get a reference to the constructor; the name is <init>
-    constructor = CBENVPTR->GetMethodID(CBENVPAR cls, "<init>", "(JJIIJJJJJLhdf/hdf5lib/structs/H5O_hdr_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;Lhdf/hdf5lib/structs/H5_ih_info_t;)V");
-    if (constructor == 0) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-    cb_info_t = CBENVPTR->NewObjectA(CBENVPAR cls, constructor, args);
-
-    status = CBENVPTR->CallIntMethod(CBENVPAR visit_callback, mid, g_id, str, cb_info_t, op_data);
-
     JVMPTR->DetachCurrentThread(JVMPAR);
 
     return status;
@@ -453,17 +439,16 @@ Java_hdf_hdf5lib_H5_H5Ovisit
 
     if (op_data == NULL) {
         h5nullArgument(env, "H5Ovisit:  op_data is NULL");
-        return -1;
     } /* end if */
-    if (callback_op == NULL) {
+    else if (callback_op == NULL) {
         h5nullArgument(env, "H5Ovisit:  callback_op is NULL");
-        return -1;
     } /* end if */
+    else {
+        status = H5Ovisit((hid_t)grp_id, (H5_index_t)idx_type, (H5_iter_order_t)order, (H5O_iterate_t)H5O_iterate_cb, (void*)op_data);
 
-    status = H5Ovisit((hid_t)grp_id, (H5_index_t)idx_type, (H5_iter_order_t)order, (H5O_iterate_t)H5O_iterate_cb, (void*)op_data);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return status;
 } /* end Java_hdf_hdf5lib_H5_H5Ovisit */
@@ -488,19 +473,21 @@ Java_hdf_hdf5lib_H5_H5Ovisit_1by_1name
         h5nullArgument(env, "H5Ovisit_by_name:  op_data is NULL");
         return -1;
     } /* end if */
-    if (callback_op == NULL) {
+    else if (callback_op == NULL) {
         h5nullArgument(env, "H5Ovisit_by_name:  callback_op is NULL");
         return -1;
     } /* end if */
+    else {
+        PIN_JAVA_STRING(name, lName);
+        if (lName != NULL) {
+            status = H5Ovisit_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (H5O_iterate_t)H5O_iterate_cb, (void*)op_data, (hid_t)access_id);
 
-    PIN_JAVA_STRING(name, lName, -1);
-
-    status = H5Ovisit_by_name((hid_t)grp_id, lName, (H5_index_t)idx_type, (H5_iter_order_t)order, (H5O_iterate_t)H5O_iterate_cb, (void*)op_data, (hid_t)access_id);
-
-    UNPIN_JAVA_STRING(name, lName);
+            UNPIN_JAVA_STRING(name, lName);
 
-    if (status < 0)
-        h5libraryError(env);
+            if (status < 0)
+                h5libraryError(env);
+        }
+    }
 
     return status;
 } /* end Java_hdf_hdf5lib_H5_H5Ovisit_1by_1name */
@@ -515,24 +502,20 @@ Java_hdf_hdf5lib_H5_H5Oset_1comment
     (JNIEnv *env, jclass clss, jlong loc_id, jstring comment)
 {
     herr_t      status = -1;
-    const char *oComment;
+    const char *oComment = NULL;
     jboolean    isCopy;
 
     if (comment == NULL) {
-        oComment = NULL;
+        status = H5Oset_comment((hid_t)loc_id, oComment);
     } /* end if */
     else {
         oComment = ENVPTR->GetStringUTFChars(ENVPAR comment, &isCopy);
-        if (oComment == NULL) {
-            h5JNIFatalError( env, "H5Oset_comment:  comment not pinned");
-            return;
-        } /* end if */
-    } /* end else */
-
-    status = H5Oset_comment((hid_t)loc_id, oComment);
+        if (oComment != NULL) {
+            status = H5Oset_comment((hid_t)loc_id, oComment);
 
-    if(oComment)
-        ENVPTR->ReleaseStringUTFChars(ENVPAR comment, oComment);
+            ENVPTR->ReleaseStringUTFChars(ENVPAR comment, oComment);
+        }
+    } /* end else */
 
     if (status < 0)
         h5libraryError(env);
@@ -552,30 +535,25 @@ Java_hdf_hdf5lib_H5_H5Oset_1comment_1by_1name
     const char *oName;
     const char *oComment;
 
-    PIN_JAVA_STRING0(name, oName);
-
-    if (comment == NULL) {
-        oComment = NULL;
-    } /* end if */
-    else {
-        jboolean    isCopy;
-        oComment = ENVPTR->GetStringUTFChars(ENVPAR comment, &isCopy);
-        if (oComment == NULL) {
-            UNPIN_JAVA_STRING(name, oName);
-            h5JNIFatalError( env, "H5Oset_comment_by_name:  comment not pinned");
-            return;
+    PIN_JAVA_STRING(name, oName);
+    if (oName != NULL) {
+        if (comment == NULL) {
+            status = H5Oset_comment_by_name((hid_t)loc_id, oName, NULL, (hid_t)access_id);
         } /* end if */
-    } /* end else */
-
-    status = H5Oset_comment_by_name((hid_t)loc_id, oName, oComment, (hid_t)access_id);
+        else {
+            jboolean    isCopy;
+            oComment = ENVPTR->GetStringUTFChars(ENVPAR comment, &isCopy);
+            if (oComment != NULL) {
+                status = H5Oset_comment_by_name((hid_t)loc_id, oName, oComment, (hid_t)access_id);
+                ENVPTR->ReleaseStringUTFChars(ENVPAR comment, oComment);
+            } /* end if */
+        } /* end else */
 
-    UNPIN_JAVA_STRING(name, oName);
-
-    if(oComment)
-        ENVPTR->ReleaseStringUTFChars(ENVPAR comment, oComment);
+        UNPIN_JAVA_STRING(name, oName);
 
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Oset_1comment_1by_1name */
 
 /*
@@ -596,34 +574,30 @@ Java_hdf_hdf5lib_H5_H5Oget_1comment
     buf_size = H5Oget_comment((hid_t)loc_id, NULL, 0);
     if (buf_size < 0) {
         h5badArgument( env, "H5Oget_comment:  buf_size < 0");
-        return NULL;
-    } /* end if */
-    if (buf_size == 0) {
-        return NULL;
     } /* end if */
-
-    buf_size++; /* add extra space for the null terminator */
-    oComment = (char *)HDmalloc(sizeof(char) * (size_t)buf_size);
-    if (oComment == NULL) {
-        /* exception -- out of memory */
-        h5outOfMemory( env, "H5Oget_comment:  malloc failed");
-        return NULL;
-    } /* end if */
-
-    status = H5Oget_comment((hid_t)loc_id, oComment, (size_t)buf_size);
-
-    if (status >= 0) {
-        /*  may throw OutOfMemoryError */
-        str = ENVPTR->NewStringUTF(ENVPAR oComment);
-        HDfree(oComment);
-        if (str == NULL) {
-            h5JNIFatalError( env, "H5Oget_comment:  return string not allocated");
+    else if (buf_size > 0) {
+        buf_size++; /* add extra space for the null terminator */
+        oComment = (char *)HDmalloc(sizeof(char) * (size_t)buf_size);
+        if (oComment == NULL) {
+            /* exception -- out of memory */
+            h5outOfMemory( env, "H5Oget_comment:  malloc failed");
         } /* end if */
-    } /* end if */
-    else {
-        HDfree(oComment);
-        h5libraryError(env);
-    } /* end else */
+        else {
+            status = H5Oget_comment((hid_t)loc_id, oComment, (size_t)buf_size);
+
+            if (status < 0) {
+                h5libraryError(env);
+            } /* end if */
+            else {
+                /*  may throw OutOfMemoryError */
+                str = ENVPTR->NewStringUTF(ENVPAR oComment);
+                if (str == NULL) {
+                    h5JNIFatalError( env, "H5Oget_comment:  return string not allocated");
+                } /* end if */
+            } /* end else */
+            HDfree(oComment);
+        }
+    } /* end else if */
 
     return (jstring)str;
 } /* end Java_hdf_hdf5lib_H5_H5Oget_1comment */
@@ -643,43 +617,37 @@ Java_hdf_hdf5lib_H5_H5Oget_1comment_1by_1name
     ssize_t     status;
     jstring     str = NULL;
 
-    PIN_JAVA_STRING(name, oName, NULL);
-
-    /* get the length of the comment */
-    buf_size = H5Oget_comment_by_name((hid_t)loc_id, oName, NULL, 0, (hid_t)access_id);
-    if (buf_size < 0) {
-        UNPIN_JAVA_STRING(name, oName);
-        h5badArgument( env, "H5Oget_comment_by_name:  buf_size < 0");
-        return NULL;
-    } /* end if */
-    if (buf_size == 0) {
-        UNPIN_JAVA_STRING(name, oName);
-        return NULL;
-    } /* end if */
-
-    buf_size++; /* add extra space for the null terminator */
-    oComment = (char *)HDmalloc(sizeof(char) * (size_t)buf_size);
-    if (oComment == NULL) {
-        UNPIN_JAVA_STRING(name, oName);
-        h5outOfMemory( env, "H5Oget_comment_by_name:  malloc failed");
-        return NULL;
-    } /* end if */
-
-    status = H5Oget_comment_by_name((hid_t)loc_id, oName, oComment, (size_t)buf_size, (hid_t)access_id);
-    UNPIN_JAVA_STRING(name, oName);
-
-    if (status >= 0) {
-        /*  may throw OutOfMemoryError */
-        str = ENVPTR->NewStringUTF(ENVPAR oComment);
-        HDfree(oComment);
-        if (str == NULL) {
-            h5JNIFatalError( env, "H5Oget_comment_by_name:  return string not allocated");
+    PIN_JAVA_STRING(name, oName);
+    if (oName != NULL) {
+        /* get the length of the comment */
+        buf_size = H5Oget_comment_by_name((hid_t)loc_id, oName, NULL, 0, (hid_t)access_id);
+        if (buf_size < 0) {
+            h5badArgument( env, "H5Oget_comment_by_name:  buf_size < 0");
         } /* end if */
-    } /* end if */
-    else {
-        HDfree(oComment);
-        h5libraryError(env);
-    } /* end else */
+        else if (buf_size > 0) {
+            buf_size++; /* add extra space for the null terminator */
+            oComment = (char *)HDmalloc(sizeof(char) * (size_t)buf_size);
+            if (oComment == NULL) {
+                h5outOfMemory( env, "H5Oget_comment_by_name:  malloc failed");
+            } /* end if */
+            else {
+                status = H5Oget_comment_by_name((hid_t)loc_id, oName, oComment, (size_t)buf_size, (hid_t)access_id);
+
+                if (status < 0) {
+                    h5libraryError(env);
+                } /* end if */
+                else {
+                    /*  may throw OutOfMemoryError */
+                    str = ENVPTR->NewStringUTF(ENVPAR oComment);
+                    if (str == NULL) {
+                        h5JNIFatalError( env, "H5Oget_comment_by_name:  return string not allocated");
+                    } /* end if */
+                } /* end else */
+                HDfree(oComment);
+            }
+        } /* end if */
+        UNPIN_JAVA_STRING(name, oName);
+    }
 
     return (jstring)str;
 } /* end Java_hdf_hdf5lib_H5_H5Oget_1comment_1by_1name */
@@ -696,16 +664,17 @@ Java_hdf_hdf5lib_H5_H5Oexists_1by_1name
     htri_t      bval = JNI_FALSE;
     const char *oName;
 
-    PIN_JAVA_STRING(name, oName, JNI_FALSE);
-
-    bval = H5Oexists_by_name((hid_t)loc_id, oName, (hid_t)access_id);
+    PIN_JAVA_STRING(name, oName);
+    if (oName != NULL) {
+        bval = H5Oexists_by_name((hid_t)loc_id, oName, (hid_t)access_id);
 
-    UNPIN_JAVA_STRING(name, oName);
+        UNPIN_JAVA_STRING(name, oName);
 
-    if (bval > 0)
-        bval = JNI_TRUE;
-    else if (bval < 0)
-        h5libraryError(env);
+        if (bval > 0)
+            bval = JNI_TRUE;
+        else if (bval < 0)
+            h5libraryError(env);
+    }
 
     return (jboolean)bval;
 } /* end Java_hdf_hdf5lib_H5_H5Oexists_1by_1name */
@@ -767,14 +736,15 @@ Java_hdf_hdf5lib_H5__1H5Oopen_1by_1idx
     hid_t       retVal = -1;
     const char *oName;
 
-    PIN_JAVA_STRING(name, oName, -1);
+    PIN_JAVA_STRING(name, oName);
+    if (oName != NULL) {
+        retVal = H5Oopen_by_idx((hid_t)loc_id, oName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (hid_t)lapl_id );
 
-    retVal = H5Oopen_by_idx((hid_t)loc_id, oName, (H5_index_t)index_field, (H5_iter_order_t)order, (hsize_t)link_n, (hid_t)lapl_id );
+        UNPIN_JAVA_STRING(name, oName);
 
-    UNPIN_JAVA_STRING(name, oName);
-
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)retVal;
 } /* end Java_hdf_hdf5lib_H5__1H5Oopen_1by_1idx */
@@ -786,7 +756,7 @@ Java_hdf_hdf5lib_H5__1H5Oopen_1by_1idx
  */
 JNIEXPORT void JNICALL
 Java_hdf_hdf5lib_H5_H5Oflush
-	(JNIEnv *env, jclass clss, jlong loc_id)
+    (JNIEnv *env, jclass clss, jlong loc_id)
 {
     if (H5Oflush((hid_t)loc_id) < 0)
         h5libraryError(env);
@@ -799,7 +769,7 @@ Java_hdf_hdf5lib_H5_H5Oflush
  */
 JNIEXPORT void JNICALL
 Java_hdf_hdf5lib_H5_H5Orefresh
-	(JNIEnv *env, jclass clss, jlong loc_id)
+    (JNIEnv *env, jclass clss, jlong loc_id)
 {
     if (H5Orefresh((hid_t)loc_id) < 0)
         h5libraryError(env);
diff --git a/java/src/jni/h5pImp.c b/java/src/jni/h5pImp.c
index 11dcbe5..ad79733 100644
--- a/java/src/jni/h5pImp.c
+++ b/java/src/jni/h5pImp.c
@@ -632,14 +632,15 @@ Java_hdf_hdf5lib_H5_H5Pset_1external
     off = (off_t)offset;
     sz = (hsize_t)size;
 
-    PIN_JAVA_STRING(name, fileName, -1);
+    PIN_JAVA_STRING(name, fileName);
+    if (fileName != NULL) {
+        status = H5Pset_external(plid, fileName, off, sz);
 
-    status = H5Pset_external(plid, fileName, off, sz);
+        UNPIN_JAVA_STRING(name, fileName);
 
-    UNPIN_JAVA_STRING(name, fileName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1external */
@@ -675,66 +676,57 @@ Java_hdf_hdf5lib_H5_H5Pget_1external
     herr_t   status = -1;
     jlong   *theArray;
     jboolean isCopy;
-    char    *file;
+    char    *file = NULL;
     jstring  str;
     off_t    o;
     hsize_t  s;
 
     if (name_size < 0) {
         h5badArgument(env, "H5Pget_external:  name_size < 0");
-        return -1;
     } /* end if */
-    else if (name_size == 0) {
-        file = NULL;
+    else if ((size != NULL) && (ENVPTR->GetArrayLength(ENVPAR size) < 2)) {
+        h5badArgument(env, "H5Pget_external:  size input array < 2");
     } /* end else if */
     else {
-        file = (char *)HDmalloc(sizeof(char)*(size_t)name_size);
-    } /* end else */
+        if (name_size > 0) {
+            file = (char *)HDmalloc(sizeof(char)*(size_t)name_size);
+        } /* end else */
 
-    if (size != NULL) {
-        if (ENVPTR->GetArrayLength(ENVPAR size) < 2) {
-            HDfree(file);
-            h5badArgument(env, "H5Pget_external:  size input array < 2");
-            return -1;
-        } /* end if */
-        theArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR size, &isCopy);
-        if (theArray == NULL) {
+        status = H5Pget_external((hid_t) plist, (unsigned)idx, (size_t)name_size,
+                file, (off_t *)&o, (hsize_t *)&s);
+        if (status < 0) {
             HDfree(file);
-            h5JNIFatalError( env, "H5Pget_external:  size array not pinned");
-            return -1;
-        } /* end if */
-    } /* end if */
-
-    status = H5Pget_external((hid_t) plist, (unsigned)idx, (size_t)name_size,
-            file, (off_t *)&o, (hsize_t *)&s);
-    if (status < 0) {
-        if (size != NULL) {
-            ENVPTR->ReleaseLongArrayElements(ENVPAR size, theArray, JNI_ABORT);
-        } /* end if */
-        HDfree(file);
-        h5libraryError(env);
-    } /* end if */
-    else {
-        if (size != NULL) {
-            theArray[0] = o;
-            theArray[1] = (jlong)s;
-            ENVPTR->ReleaseLongArrayElements(ENVPAR size, theArray, 0);
+            h5libraryError(env);
         } /* end if */
+        else {
+            if (size != NULL) {
+                theArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR size, &isCopy);
+                if (theArray == NULL) {
+                    h5JNIFatalError( env, "H5Pget_external:  size array not pinned");
+                } /* end if */
+                else {
+                    theArray[0] = o;
+                    theArray[1] = (jlong)s;
+                    ENVPTR->ReleaseLongArrayElements(ENVPAR size, theArray, 0);
+                }
+            } /* end if */
 
-        if (file != NULL) {
-            /*  NewStringUTF may throw OutOfMemoryError */
-            str = ENVPTR->NewStringUTF(ENVPAR file);
-            if (str == NULL) {
-                HDfree(file);
-                h5JNIFatalError(env, "H5Pget_external:  return array not created");
+            if (file != NULL) {
+                /*  NewStringUTF may throw OutOfMemoryError */
+                str = ENVPTR->NewStringUTF(ENVPAR file);
+                if (str == NULL) {
+                    HDfree(file);
+                    h5JNIFatalError(env, "H5Pget_external:  return array not created");
+                } /* end if */
+                else {
+                    /*  SetObjectArrayElement may raise exceptions */
+                    ENVPTR->SetObjectArrayElement(ENVPAR name, 0, (jobject)str);
+                    HDfree(file);
+                } /* end else */
             } /* end if */
-            else {
-                /*  SetObjectArrayElement may raise exceptions */
-                ENVPTR->SetObjectArrayElement(ENVPAR name, 0, (jobject)str);
-                HDfree(file);
-            } /* end else */
-        } /* end if */
-    } /* end else */
+        } /* end else */
+    }
+
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Pget_1external */
 
@@ -748,26 +740,28 @@ Java_hdf_hdf5lib_H5_H5Pset_1fill_1value
     (JNIEnv *env, jclass clss, jlong plist_id, jlong type_id, jbyteArray value)
 {
     jint     status = -1;
-    jbyte   *byteP;
+    jbyte   *byteP = NULL;
     jboolean isCopy;
 
     if (value != NULL) {
         byteP = ENVPTR->GetByteArrayElements(ENVPAR value, &isCopy);
         if (byteP == NULL) {
             h5JNIFatalError(env, "H5Pget_fill_value:  value array not pinned");
-            return -1;
         } /* end if */
-    } /* end if */
-
-    status = H5Pset_fill_value((hid_t)plist_id, (hid_t)type_id, byteP);
+        else {
+            status = H5Pset_fill_value((hid_t)plist_id, (hid_t)type_id, byteP);
 
-    if (value != NULL)
-        ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, JNI_ABORT);
+            ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, JNI_ABORT);
+        }
+    } /* end if */
+    else {
+        status = H5Pset_fill_value((hid_t)plist_id, (hid_t)type_id, byteP);
+    }
 
     if (status < 0)
         h5libraryError(env);
 
-    return status;
+    return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1fill_1value */
 
 /*
@@ -802,7 +796,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1fill_1value
         } /* end else */
     } /* end else */
 
-    return status;
+    return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Pget_1fill_1value */
 
 /*
@@ -874,6 +868,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1filter
     jint    *flagsArray;
     jlong   *cd_nelmtsArray;
     jint    *cd_valuesArray;
+    jint     mode = JNI_ABORT;
     jboolean isCopy;
     jstring  str;
     char    *filter;
@@ -893,65 +888,59 @@ Java_hdf_hdf5lib_H5_H5Pget_1filter
     else {
         filter = (char *)HDmalloc(sizeof(char)*(size_t)namelen);
         if (filter == NULL) {
-            h5outOfMemory(env, "H5Pget_filter:  namelent malloc failed");
-            return -1;
-        } /* end if */
-        flagsArray = (jint *)ENVPTR->GetIntArrayElements(ENVPAR flags, &isCopy);
-        if (flagsArray == NULL) {
-            HDfree(filter);
-            h5JNIFatalError(env, "H5Pget_filter:  flags array not pinned");
-            return -1;
-        } /* end if */
-        cd_nelmtsArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR cd_nelmts, &isCopy);
-        if (cd_nelmtsArray == NULL) {
-            ENVPTR->ReleaseIntArrayElements(ENVPAR flags, flagsArray, JNI_ABORT);
-            HDfree(filter);
-            h5JNIFatalError(env, "H5Pget_filter:  nelmts array not pinned");
-            return -1;
-        } /* end if */
-        cd_valuesArray = (jint *)ENVPTR->GetIntArrayElements(ENVPAR cd_values, &isCopy);
-        if (cd_valuesArray == NULL)  {
-            ENVPTR->ReleaseLongArrayElements(ENVPAR cd_nelmts, cd_nelmtsArray, JNI_ABORT);
-            ENVPTR->ReleaseIntArrayElements(ENVPAR flags, flagsArray, JNI_ABORT);
-            HDfree(filter);
-            h5JNIFatalError(env, "H5Pget_filter:  elmts array not pinned");
-            return -1;
-        } /* end if */
-
-        { /* direct cast (size_t *)variable fails on 32-bit environment */
-            long long cd_nelmts_temp = *(cd_nelmtsArray);
-            size_t cd_nelmts_t = (size_t)cd_nelmts_temp;
-            unsigned int filter_config;
-            status = H5Pget_filter2((hid_t)plist, (unsigned)filter_number,
-                (unsigned int *)flagsArray, &cd_nelmts_t, (unsigned int *)cd_valuesArray,
-                (size_t)namelen, filter, &filter_config);
-
-            *cd_nelmtsArray = (jlong)cd_nelmts_t;
-        } /* end direct cast special */
-
-        if (status < 0) {
-            ENVPTR->ReleaseIntArrayElements(ENVPAR cd_values, cd_valuesArray, JNI_ABORT);
-            ENVPTR->ReleaseLongArrayElements(ENVPAR cd_nelmts, cd_nelmtsArray, JNI_ABORT);
-            ENVPTR->ReleaseIntArrayElements(ENVPAR flags, flagsArray, JNI_ABORT);
-            HDfree(filter);
-            h5libraryError(env);
+            h5outOfMemory(env, "H5Pget_filter:  namelen malloc failed");
         } /* end if */
         else {
-            ENVPTR->ReleaseIntArrayElements(ENVPAR cd_values, cd_valuesArray, 0);
-            ENVPTR->ReleaseLongArrayElements(ENVPAR cd_nelmts, cd_nelmtsArray, 0);
-            ENVPTR->ReleaseIntArrayElements(ENVPAR flags, flagsArray, 0);
-
-            /*  NewStringUTF may throw OutOfMemoryError */
-            str = ENVPTR->NewStringUTF(ENVPAR filter);
-            HDfree(filter);
-            if (str == NULL) {
-                h5JNIFatalError(env, "H5Pget_filter:  return string not pinned");
+            flagsArray = (jint *)ENVPTR->GetIntArrayElements(ENVPAR flags, &isCopy);
+            if (flagsArray == NULL) {
+                h5JNIFatalError(env, "H5Pget_filter:  flags array not pinned");
             } /* end if */
             else {
-                /*  SetObjectArrayElement may throw exceptiosn */
-                ENVPTR->SetObjectArrayElement(ENVPAR name, 0, (jobject)str);
-            } /* end else */
-        } /* end else */
+                cd_nelmtsArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR cd_nelmts, &isCopy);
+                if (cd_nelmtsArray == NULL) {
+                    h5JNIFatalError(env, "H5Pget_filter:  nelmts array not pinned");
+                } /* end if */
+                else {
+                    cd_valuesArray = (jint *)ENVPTR->GetIntArrayElements(ENVPAR cd_values, &isCopy);
+                    if (cd_valuesArray == NULL)  {
+                        h5JNIFatalError(env, "H5Pget_filter:  elmts array not pinned");
+                    } /* end if */
+                    else {
+                        /* direct cast (size_t *)variable fails on 32-bit environment */
+                        long long cd_nelmts_temp = *(cd_nelmtsArray);
+                        size_t cd_nelmts_t = (size_t)cd_nelmts_temp;
+                        unsigned int filter_config;
+                        status = H5Pget_filter2((hid_t)plist, (unsigned)filter_number,
+                                (unsigned int *)flagsArray, &cd_nelmts_t, (unsigned int *)cd_valuesArray,
+                                (size_t)namelen, filter, &filter_config);
+
+                        *cd_nelmtsArray = (jlong)cd_nelmts_t;
+                        /* end direct cast special */
+
+                        if (status < 0) {
+                            h5libraryError(env);
+                        } /* end if */
+                        else {
+                            mode = 0;
+
+                            /*  NewStringUTF may throw OutOfMemoryError */
+                            str = ENVPTR->NewStringUTF(ENVPAR filter);
+                            if (str == NULL) {
+                                h5JNIFatalError(env, "H5Pget_filter:  return string not pinned");
+                            } /* end if */
+                            else {
+                                /*  SetObjectArrayElement may throw exceptiosn */
+                                ENVPTR->SetObjectArrayElement(ENVPAR name, 0, (jobject)str);
+                            } /* end else */
+                        } /* end else */
+                        ENVPTR->ReleaseIntArrayElements(ENVPAR cd_values, cd_valuesArray, mode);
+                    }
+                    ENVPTR->ReleaseLongArrayElements(ENVPAR cd_nelmts, cd_nelmtsArray, mode);
+                }
+                ENVPTR->ReleaseIntArrayElements(ENVPAR flags, flagsArray, mode);
+            }
+            HDfree(filter);
+        }
     } /* end else */
 
     return (jint)status;
@@ -1007,15 +996,12 @@ Java_hdf_hdf5lib_H5_H5Pget_1cache
 {
     herr_t   status = -1;
     jint     mode;
-    jdouble *w0Array;
-    jlong   *rdcc_nelmtsArray;
-    jlong   *nbytesArray;
+    jdouble *w0Array = (jdouble *)NULL;
+    jlong   *rdcc_nelmtsArray = (jlong *)NULL;
+    jlong   *nbytesArray = (jlong *)NULL;
     jboolean isCopy;
 
-    if (rdcc_w0 == NULL) {
-        w0Array = (jdouble *)NULL;
-    } /* end if */
-    else {
+    if (rdcc_w0 != NULL) {
         w0Array = (jdouble *)ENVPTR->GetDoubleArrayElements(ENVPAR rdcc_w0, &isCopy);
         if (w0Array == NULL) {
             h5JNIFatalError(env, "H5Pget_cache:  w0_array array not pinned");
@@ -1023,10 +1009,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1cache
         } /* end if */
     } /* end else */
 
-    if (rdcc_nelmts == NULL) {
-        rdcc_nelmtsArray = (jlong *) NULL;
-    } /* end if */
-    else {
+    if (rdcc_nelmts != NULL) {
         rdcc_nelmtsArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR rdcc_nelmts, &isCopy);
         if (rdcc_nelmtsArray == NULL) {
             /* exception -- out of memory */
@@ -1038,10 +1021,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1cache
         } /* end if */
     } /* end else */
 
-    if (rdcc_nbytes == NULL) {
-        nbytesArray = (jlong *) NULL;
-    } /* end if */
-    else {
+    if (rdcc_nbytes != NULL) {
         nbytesArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR rdcc_nbytes, &isCopy);
         if (nbytesArray == NULL) {
             if (w0Array != NULL) {
@@ -1148,7 +1128,7 @@ Java_hdf_hdf5lib_H5_H5Pset_1buffer
     if (bkg != NULL)
         ENVPTR->ReleaseByteArrayElements(ENVPAR bkg, bkgP, 0);
 
-    return status;
+    return (jint)status;
 #endif
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1buffer */
 
@@ -1200,7 +1180,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1buffer
     ENVPTR->ReleaseByteArrayElements(ENVPAR tconv, tconvP, 0);
     ENVPTR->ReleaseByteArrayElements(ENVPAR bkg, bkgP, 0);
 
-    return status;
+    return (jint)status;
 #endif
 } /* end Java_hdf_hdf5lib_H5_H5Pget_1buffer */
 
@@ -1998,6 +1978,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1fapl_1family
     herr_t   status = -1;
     jlong   *sizeArray;
     jlong   *plistArray;
+    jint     mode = JNI_ABORT;
     jboolean isCopy;
     hsize_t *sa;
     size_t   i;
@@ -2013,39 +1994,36 @@ Java_hdf_hdf5lib_H5_H5Pget_1fapl_1family
         sizeArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR memb_size, &isCopy);
         if (sizeArray == NULL) {
             h5JNIFatalError(env,  "H5Pget_family:  sizeArray not pinned");
-            return -1;
-        } /* end if */
-        rank = (size_t)ENVPTR->GetArrayLength(ENVPAR  memb_size);
-        sa = (hsize_t *)HDmalloc(rank * sizeof(hsize_t));
-        if (sa == NULL) {
-            ENVPTR->ReleaseLongArrayElements(ENVPAR memb_size, sizeArray, JNI_ABORT);
-            h5JNIFatalError(env,  "H5Screate-simple:  dims not converted to hsize_t");
-            return -1;
-        } /* end if */
-        plistArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR memb_plist, &isCopy);
-        if (plistArray == NULL) {
-            HDfree(sa);
-            ENVPTR->ReleaseLongArrayElements(ENVPAR memb_size, sizeArray, JNI_ABORT);
-            h5JNIFatalError(env,  "H5Pget_family:  plistArray not pinned");
-            return -1;
-        } /* end if */
-
-        status = H5Pget_fapl_family ((hid_t)tid, sa, (hid_t *)plistArray);
-
-        if (status < 0) {
-            HDfree(sa);
-            ENVPTR->ReleaseLongArrayElements(ENVPAR memb_size, sizeArray, JNI_ABORT);
-            ENVPTR->ReleaseLongArrayElements(ENVPAR memb_plist, plistArray, JNI_ABORT);
-            h5libraryError(env);
         } /* end if */
         else {
-            for (i = 0; i < rank; i++) {
-                sizeArray[i] = (jlong)sa[i];
-            } /* end for */
-            HDfree(sa);
-            ENVPTR->ReleaseLongArrayElements(ENVPAR memb_size, sizeArray, 0);
-            ENVPTR->ReleaseLongArrayElements(ENVPAR memb_plist, plistArray, 0);
-        } /* end else */
+            rank = (size_t)ENVPTR->GetArrayLength(ENVPAR  memb_size);
+            sa = (hsize_t *)HDmalloc(rank * sizeof(hsize_t));
+            if (sa == NULL) {
+                h5JNIFatalError(env,  "H5Screate-simple:  dims not converted to hsize_t");
+            } /* end if */
+            else {
+                plistArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR memb_plist, &isCopy);
+                if (plistArray == NULL) {
+                    h5JNIFatalError(env,  "H5Pget_family:  plistArray not pinned");
+                } /* end if */
+                else {
+                    status = H5Pget_fapl_family ((hid_t)tid, sa, (hid_t *)plistArray);
+
+                    if (status < 0) {
+                        h5libraryError(env);
+                    } /* end if */
+                    else {
+                        for (i = 0; i < rank; i++) {
+                            sizeArray[i] = (jlong)sa[i];
+                        } /* end for */
+                        mode = 0;
+                    } /* end else */
+                    ENVPTR->ReleaseLongArrayElements(ENVPAR memb_plist, plistArray, mode);
+                }
+                HDfree(sa);
+            }
+            ENVPTR->ReleaseLongArrayElements(ENVPAR memb_size, sizeArray, mode);
+        }
     } /* end else */
 
     return (jint)status;
@@ -2079,6 +2057,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1fapl_1core
     (JNIEnv *env, jclass clss, jlong fapl_id, jlongArray increment, jbooleanArray backing_store)
 {
     herr_t    status = -1;
+    jint      mode = JNI_ABORT;
     jlong    *incArray;
     jboolean *backArray;
     jboolean  isCopy;
@@ -2093,34 +2072,32 @@ Java_hdf_hdf5lib_H5_H5Pget_1fapl_1core
         incArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR increment, &isCopy);
         if (incArray == NULL) {
             h5JNIFatalError(env,  "H5Pget_fapl_core:  incArray not pinned");
-            return -1;
-        } /* end if */
-
-        backArray = (jboolean *)ENVPTR->GetBooleanArrayElements(ENVPAR backing_store, &isCopy);
-        if (backArray == NULL) {
-            ENVPTR->ReleaseLongArrayElements(ENVPAR increment, incArray, JNI_ABORT);
-            h5JNIFatalError(env, "H5Pget_fapl_core:  backArray not pinned");
-            return -1;
         } /* end if */
+        else {
+            backArray = (jboolean *)ENVPTR->GetBooleanArrayElements(ENVPAR backing_store, &isCopy);
+            if (backArray == NULL) {
+                h5JNIFatalError(env, "H5Pget_fapl_core:  backArray not pinned");
+            } /* end if */
+            else {
+                /* direct cast (size_t *)variable fails on 32-bit environment */
+                long long inc_temp = *(incArray);
+                size_t inc_t = (size_t)inc_temp;
 
-        { /* direct cast (size_t *)variable fails on 32-bit environment */
-            long long inc_temp = *(incArray);
-            size_t inc_t = (size_t)inc_temp;
-
-            status = H5Pget_fapl_core((hid_t)fapl_id, &inc_t, (hbool_t *)backArray);
+                status = H5Pget_fapl_core((hid_t)fapl_id, &inc_t, (hbool_t *)backArray);
 
-            *incArray = (jlong)inc_t;
-        } /* end direct cast special */
+                *incArray = (jlong)inc_t;
+                /* end direct cast special */
 
-        if (status < 0) {
-            ENVPTR->ReleaseLongArrayElements(ENVPAR increment, incArray, JNI_ABORT);
-            ENVPTR->ReleaseBooleanArrayElements(ENVPAR backing_store, backArray, JNI_ABORT);
-            h5libraryError(env);
-        } /* end if */
-        else {
-            ENVPTR->ReleaseLongArrayElements(ENVPAR increment, incArray, 0);
-            ENVPTR->ReleaseBooleanArrayElements(ENVPAR backing_store, backArray, 0);
-        } /* end else */
+                if (status < 0) {
+                    h5libraryError(env);
+                } /* end if */
+                else {
+                    mode = 0;
+                } /* end else */
+                ENVPTR->ReleaseBooleanArrayElements(ENVPAR backing_store, backArray, mode);
+            }
+            ENVPTR->ReleaseLongArrayElements(ENVPAR increment, incArray, mode);
+        }
     } /* end else */
 
     return (jint)status;
@@ -2175,14 +2152,15 @@ Java_hdf_hdf5lib_H5_H5Pset_1fapl_1log
     herr_t      retVal = -1;
     const char *pLogfile;
 
-    PIN_JAVA_STRING0(logfile, pLogfile);
-
-    retVal = H5Pset_fapl_log( (hid_t)fapl_id, pLogfile, (unsigned long long)flags, (size_t)buf_size );
+    PIN_JAVA_STRING(logfile, pLogfile);
+    if (pLogfile != NULL) {
+        retVal = H5Pset_fapl_log( (hid_t)fapl_id, pLogfile, (unsigned long long)flags, (size_t)buf_size );
 
-    UNPIN_JAVA_STRING(logfile, pLogfile);
+        UNPIN_JAVA_STRING(logfile, pLogfile);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1fapl_1log */
 
 /*
@@ -2200,7 +2178,7 @@ Java_hdf_hdf5lib_H5_H5P1remove_1filter
     if (status < 0)
         h5libraryError(env);
 
-    return status;
+    return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5P1remove_1filter */
 
 
@@ -2216,14 +2194,15 @@ Java_hdf_hdf5lib_H5_H5Pset
     hid_t       retVal = -1;
     const char *cstr;
 
-    PIN_JAVA_STRING(name, cstr, -1);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        retVal =  H5Pset((hid_t)plid, cstr, &val);
 
-    retVal =  H5Pset((hid_t)plid, cstr, &val);
-
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Pset */
@@ -2240,16 +2219,17 @@ Java_hdf_hdf5lib_H5_H5Pexist
     htri_t bval = JNI_FALSE;
     const char *cstr;
 
-    PIN_JAVA_STRING(name, cstr, JNI_FALSE);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        bval = H5Pexist((hid_t)plid, cstr);
 
-    bval = H5Pexist((hid_t)plid, cstr);
-
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (bval > 0)
-        bval = JNI_TRUE;
-    else if (bval < 0)
-        h5libraryError(env);
+        if (bval > 0)
+            bval = JNI_TRUE;
+        else if (bval < 0)
+            h5libraryError(env);
+    }
 
     return (jboolean)bval;
 } /* end Java_hdf_hdf5lib_H5_H5Pexist */
@@ -2265,16 +2245,17 @@ Java_hdf_hdf5lib_H5_H5Pget_1size
 {
     hid_t       retVal = -1;
     const char *cstr;
-    size_t      size;
+    size_t      size = 0;
 
-    PIN_JAVA_STRING(name, cstr, -1);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        retVal = H5Pget_size((hid_t)plid, cstr, &size);
 
-    retVal = H5Pget_size((hid_t)plid, cstr, &size);
-
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jlong) size;
 } /* end Java_hdf_hdf5lib_H5_H5Pget_1size */
@@ -2306,7 +2287,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1class_1name
     (JNIEnv *env, jclass clss, jlong plid)
 {
     char   *c_str;
-    jstring j_str;
+    jstring j_str = NULL;
 
     c_str = H5Pget_class_name((hid_t)plid);
     if (c_str == NULL) {
@@ -2371,14 +2352,15 @@ Java_hdf_hdf5lib_H5_H5Pget
     const char *cstr;
     jint        val;
 
-    PIN_JAVA_STRING(name, cstr, -1);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        retVal = H5Pget((hid_t)plid, cstr, &val);
 
-    retVal = H5Pget((hid_t)plid, cstr, &val);
-
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)val;
 } /* end Java_hdf_hdf5lib_H5_H5Pget */
@@ -2413,14 +2395,15 @@ Java_hdf_hdf5lib_H5_H5Pcopy_1prop
     herr_t      retVal = -1;
     const char *cstr;
 
-    PIN_JAVA_STRING(name, cstr, -1);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        retVal = H5Pcopy_prop((hid_t)dst_plid, (hid_t)src_plid, cstr);
 
-    retVal = H5Pcopy_prop((hid_t)dst_plid, (hid_t)src_plid, cstr);
-
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Pcopy_1prop */
@@ -2437,14 +2420,15 @@ Java_hdf_hdf5lib_H5_H5Premove
     herr_t      retVal = -1;
     const char *cstr;
 
-    PIN_JAVA_STRING(name, cstr, -1);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        retVal = H5Premove((hid_t)plid, cstr);
 
-    retVal = H5Premove((hid_t)plid, cstr);
-
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Premove */
@@ -2461,14 +2445,15 @@ Java_hdf_hdf5lib_H5_H5Punregister
     herr_t      retVal = -1;
     const char *cstr;
 
-    PIN_JAVA_STRING(name, cstr, -1);
-
-    retVal = H5Punregister((hid_t)plid, cstr);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        retVal = H5Punregister((hid_t)plid, cstr);
 
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Punregister */
@@ -2976,14 +2961,15 @@ Java_hdf_hdf5lib_H5_H5Pset_1data_1transform
     herr_t      retVal = -1;
     const char *express;
 
-    PIN_JAVA_STRING(expression, express, -1);
-
-    retVal = H5Pset_data_transform((hid_t)plist_id, express);
+    PIN_JAVA_STRING(expression, express);
+    if (express != NULL) {
+        retVal = H5Pset_data_transform((hid_t)plist_id, express);
 
-    UNPIN_JAVA_STRING(expression, express);
+        UNPIN_JAVA_STRING(expression, express);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1data_1transform */
@@ -3566,14 +3552,15 @@ Java_hdf_hdf5lib_H5_H5Pset_1elink_1prefix
     herr_t      retVal = -1;
     const char *aName;
 
-    PIN_JAVA_STRING(prefix, aName, -1);
+    PIN_JAVA_STRING(prefix, aName);
+    if (aName != NULL) {
+        retVal = H5Pset_elink_prefix((hid_t)lapl_id, aName);
 
-    retVal = H5Pset_elink_prefix((hid_t)lapl_id, aName);
+        UNPIN_JAVA_STRING(prefix, aName);
 
-    UNPIN_JAVA_STRING(prefix, aName);
-
-    if(retVal < 0)
-        h5libraryError(env);
+        if(retVal < 0)
+            h5libraryError(env);
+    }
 
     return (jint)retVal;
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1elink_1prefix */
@@ -3589,7 +3576,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1elink_1prefix
 {
     size_t  size = 0;
     char   *pre;
-    jlong   prefix_size;
+    jlong   prefix_size = -1;
     jstring str = NULL;
 
     if (prefix == NULL) {
@@ -3966,14 +3953,15 @@ Java_hdf_hdf5lib_H5_H5Pset_1fapl_1split
     const char *mstr;
     const char *rstr;
 
-    PIN_JAVA_STRING_TWO0(metaext, mstr, rawext, rstr);
+    PIN_JAVA_STRING_TWO(metaext, mstr, rawext, rstr);
+    if (mstr != NULL && rstr != NULL) {
+        retVal = H5Pset_fapl_split((hid_t)fapl_id, mstr, (hid_t)meta_pl_id, rstr, (hid_t)raw_pl_id);
 
-    retVal = H5Pset_fapl_split((hid_t)fapl_id, mstr, (hid_t)meta_pl_id, rstr, (hid_t)raw_pl_id);
+        UNPIN_JAVA_STRING_TWO(metaext, mstr, rawext, rstr);
 
-    UNPIN_JAVA_STRING_TWO(metaext, mstr, rawext, rstr);
-
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1fapl_1split */
 
 /*
@@ -4034,7 +4022,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1sieve_1buf_1size
 {
     size_t  s;
 
-    if ( H5Pget_sieve_buf_size((hid_t)plist, &s) < 0)
+    if (H5Pget_sieve_buf_size((hid_t)plist, &s) < 0)
         h5libraryError(env);
 
     return (jlong)s;
@@ -4486,13 +4474,13 @@ Java_hdf_hdf5lib_H5_H5Pset_1mdc_1config
     cacheinfo.metadata_write_strategy = ENVPTR->GetIntField(ENVPAR cache_config, fid);
     if(ENVPTR->ExceptionOccurred(ENVONLY)) {
         h5JNIFatalError(env, "H5Pset_mdc_config: loading metadata_write_strategy failed");
-        return;
     } /* end if */
+    else {
+        status = H5Pset_mdc_config((hid_t)plist, &cacheinfo);
 
-    status = H5Pset_mdc_config((hid_t)plist, &cacheinfo);
-
-    if (status < 0)
-       h5libraryError(env);
+        if (status < 0)
+        h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1mdc_1config */
 
 /*
@@ -4521,15 +4509,12 @@ Java_hdf_hdf5lib_H5_H5Pget_1chunk_1cache
 {
     herr_t   status = -1;
     jint     mode;
-    jdouble *w0Array;
-    jlong   *rdcc_nslotsArray;
-    jlong   *nbytesArray;
+    jdouble *w0Array = (jdouble *)NULL;
+    jlong   *rdcc_nslotsArray = (jlong *)NULL;
+    jlong   *nbytesArray = (jlong *)NULL;
     jboolean isCopy;
 
-    if (rdcc_w0 == NULL) {
-        w0Array = (jdouble *)NULL;
-    } /* end if */
-    else {
+    if (rdcc_w0 != NULL) {
         w0Array = (jdouble *)ENVPTR->GetDoubleArrayElements(ENVPAR rdcc_w0, &isCopy);
         if (w0Array == NULL) {
             h5JNIFatalError(env, "H5Pget_chunk_cache:  w0_array array not pinned");
@@ -4537,10 +4522,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1chunk_1cache
         } /* end if */
     } /* end else */
 
-    if (rdcc_nslots == NULL) {
-        rdcc_nslotsArray = (jlong *)NULL;
-    } /* end if */
-    else {
+    if (rdcc_nslots != NULL) {
         rdcc_nslotsArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR rdcc_nslots, &isCopy);
         if (rdcc_nslotsArray == NULL) {
             /* exception -- out of memory */
@@ -4552,10 +4534,7 @@ Java_hdf_hdf5lib_H5_H5Pget_1chunk_1cache
         } /* end if */
     } /* end else */
 
-    if (rdcc_nbytes == NULL) {
-        nbytesArray = (jlong *)NULL;
-    } /* end if */
-    else {
+    if (rdcc_nbytes != NULL) {
         nbytesArray = (jlong *)ENVPTR->GetLongArrayElements(ENVPAR rdcc_nbytes, &isCopy);
         if (nbytesArray == NULL) {
             if (w0Array != NULL) {
@@ -4691,14 +4670,15 @@ Java_hdf_hdf5lib_H5_H5Pset_1virtual
     const char *fstr;
     const char *dstr;
 
-    PIN_JAVA_STRING_TWO0(src_file_name, fstr, src_dset_name, dstr);
-
-    retVal = H5Pset_virtual((hid_t)dcpl_id, (hid_t)vspace_id, fstr, dstr, (hid_t)src_space_id);
+    PIN_JAVA_STRING_TWO(src_file_name, fstr, src_dset_name, dstr);
+    if (fstr != NULL && dstr != NULL) {
+        retVal = H5Pset_virtual((hid_t)dcpl_id, (hid_t)vspace_id, fstr, dstr, (hid_t)src_space_id);
 
-    UNPIN_JAVA_STRING_TWO(src_file_name, fstr, src_dset_name, dstr);
+        UNPIN_JAVA_STRING_TWO(src_file_name, fstr, src_dset_name, dstr);
 
-    if (retVal < 0)
-        h5libraryError(env);
+        if (retVal < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pset_1virtual */
 
 /*
@@ -4981,7 +4961,7 @@ H5P_cls_create_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_cls_create_cb */
 
 static herr_t
@@ -4989,7 +4969,7 @@ H5P_cls_copy_cb
     (hid_t new_prop_id, hid_t old_prop_id, void *copy_data)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5004,7 +4984,7 @@ H5P_cls_copy_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_cls_ccopy_cb */
 
 static herr_t
@@ -5012,7 +4992,7 @@ H5P_cls_close_cb
     (hid_t prop_id, void *close_data)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5027,7 +5007,7 @@ H5P_cls_close_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_cls_close_cb */
 
 static herr_t
@@ -5035,7 +5015,7 @@ H5D_append_cb
     (hid_t dataset_id, hsize_t *cur_dims, void *op_data)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jlongArray cur_dimsArray;
@@ -5046,33 +5026,22 @@ H5D_append_cb
         return -1;
     } /* end if */
     cls = CBENVPTR->GetObjectClass(CBENVPAR visit_callback);
-    if (cls == 0) {
-       JVMPTR->DetachCurrentThread(JVMPAR);
-       return -1;
-    } /* end if */
-    mid = CBENVPTR->GetMethodID(CBENVPAR cls, "callback", "(J[JLhdf/hdf5lib/callbacks/H5D_append_t;)I");
-    if (mid == 0) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-
-    if (cur_dims == NULL) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
-    } /* end if */
-
-    cur_dimsArray = CBENVPTR->NewLongArray(CBENVPAR 2);
-    if (cur_dimsArray == NULL) {
-        JVMPTR->DetachCurrentThread(JVMPAR);
-        return -1;
+    if (cls != 0) {
+        mid = CBENVPTR->GetMethodID(CBENVPAR cls, "callback", "(J[JLhdf/hdf5lib/callbacks/H5D_append_t;)I");
+        if (mid != 0) {
+            if (cur_dims != NULL) {
+                cur_dimsArray = CBENVPTR->NewLongArray(CBENVPAR 2);
+                if (cur_dimsArray != NULL) {
+                    CBENVPTR->SetLongArrayRegion(CBENVPAR cur_dimsArray, 0, 2, (const jlong *)cur_dims);
+
+                    status = CBENVPTR->CallIntMethod(CBENVPAR visit_callback, mid, dataset_id, cur_dims, op_data);
+                }
+            }
+        }
     } /* end if */
-    CBENVPTR->SetLongArrayRegion(CBENVPAR cur_dimsArray, 0, 2, (const jlong *)cur_dims);
-
-    status = CBENVPTR->CallIntMethod(CBENVPAR visit_callback, mid, dataset_id, cur_dims, op_data);
-
     JVMPTR->DetachCurrentThread(JVMPAR);
 
-    return status;
+    return (herr_t)status;
 } /* end H5D_append_cb */
 
 /*
@@ -5115,14 +5084,15 @@ Java_hdf_hdf5lib_H5__1H5Pcreate_1class_1nocb
     hid_t class_id = -1;
     const char *cstr;
 
-    PIN_JAVA_STRING(name, cstr, -1);
-
-    class_id = H5Pcreate_class((hid_t)parent_class, cstr,  NULL, NULL, NULL, NULL, NULL, NULL);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        class_id = H5Pcreate_class((hid_t)parent_class, cstr,  NULL, NULL, NULL, NULL, NULL, NULL);
 
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (class_id < 0)
-        h5libraryError(env);
+        if (class_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)class_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Pcreate_1class_1nocb */
@@ -5143,15 +5113,16 @@ Java_hdf_hdf5lib_H5__1H5Pcreate_1class
     close_callback = close_op;
     create_callback = create_op;
 
-    PIN_JAVA_STRING(name, cstr, -1);
-
-    class_id = H5Pcreate_class((hid_t)parent_class, cstr, (H5P_cls_create_func_t)H5P_cls_create_cb, (void*) create_data,
-            (H5P_cls_copy_func_t)H5P_cls_copy_cb, (void*) copy_data, (H5P_cls_close_func_t)H5P_cls_close_cb, (void*) close_data);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        class_id = H5Pcreate_class((hid_t)parent_class, cstr, (H5P_cls_create_func_t)H5P_cls_create_cb, (void*) create_data,
+                (H5P_cls_copy_func_t)H5P_cls_copy_cb, (void*) copy_data, (H5P_cls_close_func_t)H5P_cls_close_cb, (void*) close_data);
 
-    UNPIN_JAVA_STRING(name, cstr);
+        UNPIN_JAVA_STRING(name, cstr);
 
-    if (class_id < 0)
-        h5libraryError(env);
+        if (class_id < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)class_id;
 } /* end Java_hdf_hdf5lib_H5__1H5Pcreate_1class */
@@ -5161,7 +5132,7 @@ H5P_prp_create_cb
     (const char *name, size_t size, void *value)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5178,7 +5149,7 @@ H5P_prp_create_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_prp_create_cb */
 
 static herr_t
@@ -5186,7 +5157,7 @@ H5P_prp_copy_cb
     (const char *name, size_t size, void *value)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5203,7 +5174,7 @@ H5P_prp_copy_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_prp_copy_cb */
 
 static herr_t
@@ -5211,7 +5182,7 @@ H5P_prp_close_cb
     (const char *name, size_t size, void *value)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5228,7 +5199,7 @@ H5P_prp_close_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_prp_close_cb */
 
 static int
@@ -5236,7 +5207,7 @@ H5P_prp_compare_cb
     (void *value1, void *value2, size_t size)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5251,7 +5222,7 @@ H5P_prp_compare_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_prp_compare_cb */
 
 static herr_t
@@ -5259,7 +5230,7 @@ H5P_prp_get_cb
     (hid_t prop_id, const char *name, size_t size, void *value)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5276,7 +5247,7 @@ H5P_prp_get_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_prp_get_cb */
 
 static herr_t
@@ -5284,7 +5255,7 @@ H5P_prp_set_cb
     (hid_t prop_id, const char *name, size_t size, void *value)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5301,7 +5272,7 @@ H5P_prp_set_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_prp_set_cb */
 
 static herr_t
@@ -5309,7 +5280,7 @@ H5P_prp_delete_cb
     (hid_t prop_id, const char *name, size_t size, void *value)
 {
     JNIEnv    *cbenv;
-    jint       status;
+    jint       status = -1;
     jclass     cls;
     jmethodID  mid;
     jmethodID  constructor;
@@ -5326,7 +5297,7 @@ H5P_prp_delete_cb
         } /* end if */
     } /* end if */
     JVMPTR->DetachCurrentThread(JVMPAR);
-    return status;
+    return (herr_t)status;
 } /* end H5P_prp_delete_cb */
 
 /*
@@ -5343,24 +5314,25 @@ Java_hdf_hdf5lib_H5_H5Pregister2_1nocb
     jboolean isCopy2;
     const char *cstr;
 
-    PIN_JAVA_STRING0(name, cstr);
-    buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
-    if (buffP == NULL) {
-        UNPIN_JAVA_STRING(name, cstr);
-        h5JNIFatalError(env, "H5Pregister2:  buf not pinned");
-    } /* end if */
-    else {
-        status = H5Pregister2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
-
-        UNPIN_JAVA_STRING(name, cstr);
-        if (status < 0) {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
-            h5libraryError(env);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
+        if (buffP == NULL) {
+            h5JNIFatalError(env, "H5Pregister2:  buf not pinned");
         } /* end if */
         else {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            status = H5Pregister2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
+
+            if (status < 0) {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
+                h5libraryError(env);
+            } /* end if */
+            else {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, cstr);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pregister2_1nocb */
 
 /*
@@ -5386,26 +5358,27 @@ Java_hdf_hdf5lib_H5_H5Pregister2
     get_callback = prp_get;
     delete_callback = prp_delete;
 
-    PIN_JAVA_STRING0(name, cstr);
-    buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
-    if (buffP == NULL) {
-        UNPIN_JAVA_STRING(name, cstr);
-        h5JNIFatalError(env, "H5Pregister2:  buf not pinned");
-    } /* end if */
-    else {
-        status = H5Pregister2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP, (H5P_prp_create_func_t)H5P_prp_create_cb,
-            (H5P_prp_set_func_t)H5P_prp_set_cb, (H5P_prp_get_func_t)H5P_prp_get_cb, (H5P_prp_delete_func_t)H5P_prp_delete_cb,
-            (H5P_prp_copy_func_t)H5P_prp_copy_cb, (H5P_prp_compare_func_t)H5P_prp_compare_cb, (H5P_prp_close_func_t)H5P_prp_close_cb);
-
-        UNPIN_JAVA_STRING(name, cstr);
-        if (status < 0) {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
-            h5libraryError(env);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
+        if (buffP == NULL) {
+            h5JNIFatalError(env, "H5Pregister2:  buf not pinned");
         } /* end if */
         else {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            status = H5Pregister2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP, (H5P_prp_create_func_t)H5P_prp_create_cb,
+                (H5P_prp_set_func_t)H5P_prp_set_cb, (H5P_prp_get_func_t)H5P_prp_get_cb, (H5P_prp_delete_func_t)H5P_prp_delete_cb,
+                (H5P_prp_copy_func_t)H5P_prp_copy_cb, (H5P_prp_compare_func_t)H5P_prp_compare_cb, (H5P_prp_close_func_t)H5P_prp_close_cb);
+
+            if (status < 0) {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
+                h5libraryError(env);
+            } /* end if */
+            else {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, cstr);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pregister2 */
 
 /*
@@ -5422,24 +5395,25 @@ Java_hdf_hdf5lib_H5_H5Pinsert2_1nocb
     jboolean isCopy2;
     const char *cstr;
 
-    PIN_JAVA_STRING0(name, cstr);
-    buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
-    if (buffP == NULL) {
-        UNPIN_JAVA_STRING(name, cstr);
-        h5JNIFatalError(env, "H5Pinsert2:  buf not pinned");
-    } /* end if */
-    else {
-        status = H5Pinsert2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP, NULL, NULL, NULL, NULL, NULL, NULL);
-
-        UNPIN_JAVA_STRING(name, cstr);
-        if (status < 0) {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
-            h5libraryError(env);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
+        if (buffP == NULL) {
+            h5JNIFatalError(env, "H5Pinsert2:  buf not pinned");
         } /* end if */
         else {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            status = H5Pinsert2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP, NULL, NULL, NULL, NULL, NULL, NULL);
+
+            if (status < 0) {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
+                h5libraryError(env);
+            } /* end if */
+            else {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, cstr);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pinsert2 */
 
 
@@ -5465,26 +5439,28 @@ Java_hdf_hdf5lib_H5_H5Pinsert2
     get_callback = prp_get;
     delete_callback = prp_delete;
 
-    PIN_JAVA_STRING0(name, cstr);
-    buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
-    if (buffP == NULL) {
-        UNPIN_JAVA_STRING(name, cstr);
-        h5JNIFatalError(env, "H5Pinsert2:  buf not pinned");
-    } /* end if */
-    else {
-        status = H5Pinsert2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP,
-            (H5P_prp_set_func_t)H5P_prp_set_cb, (H5P_prp_get_func_t)H5P_prp_get_cb, (H5P_prp_delete_func_t)H5P_prp_delete_cb,
-            (H5P_prp_copy_func_t)H5P_prp_copy_cb, (H5P_prp_compare_func_t)H5P_prp_compare_cb, (H5P_prp_close_func_t)H5P_prp_close_cb);
-
-        UNPIN_JAVA_STRING(name, cstr);
-        if (status < 0) {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
-            h5libraryError(env);
+    PIN_JAVA_STRING(name, cstr);
+    if (cstr != NULL) {
+        buffP = ENVPTR->GetByteArrayElements(ENVPAR def_value, &isCopy2);
+        if (buffP == NULL) {
+            UNPIN_JAVA_STRING(name, cstr);
+            h5JNIFatalError(env, "H5Pinsert2:  buf not pinned");
         } /* end if */
         else {
-            ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            status = H5Pinsert2((hid_t)cls_id, cstr, (size_t)prp_size, (void*)buffP,
+                (H5P_prp_set_func_t)H5P_prp_set_cb, (H5P_prp_get_func_t)H5P_prp_get_cb, (H5P_prp_delete_func_t)H5P_prp_delete_cb,
+                (H5P_prp_copy_func_t)H5P_prp_copy_cb, (H5P_prp_compare_func_t)H5P_prp_compare_cb, (H5P_prp_close_func_t)H5P_prp_close_cb);
+
+            if (status < 0) {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, JNI_ABORT);
+                h5libraryError(env);
+            } /* end if */
+            else {
+                ENVPTR->ReleaseByteArrayElements(ENVPAR def_value, buffP, 0);
+            } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, cstr);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Pinsert2 */
 
 static herr_t
@@ -5561,9 +5537,9 @@ Java_hdf_hdf5lib_H5_H5Piterate
             theArray = (jint *)ENVPTR->GetIntArrayElements(ENVPAR idx, &isCopy);
             if (theArray == NULL) {
                 h5JNIFatalError(env, "H5Piterate:  idx not pinned");
-                return -1;
             } /* end if */
-            status = H5Piterate((hid_t)prop_id, (int*)&theArray[0], (H5P_iterate_t)H5P_iterate_cb, (void*)op_data);
+            else
+                status = H5Piterate((hid_t)prop_id, (int*)&theArray[0], (H5P_iterate_t)H5P_iterate_cb, (void*)op_data);
         } /* end else */
 
         if (status < 0) {
@@ -5575,7 +5551,7 @@ Java_hdf_hdf5lib_H5_H5Piterate
             ENVPTR->ReleaseIntArrayElements(ENVPAR idx, theArray, 0);
     } /* end else */
 
-    return status;
+    return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Piterate */
 
 #ifdef __cplusplus
diff --git a/java/src/jni/h5rImp.c b/java/src/jni/h5rImp.c
index df0ea3c..647f973 100644
--- a/java/src/jni/h5rImp.c
+++ b/java/src/jni/h5rImp.c
@@ -46,45 +46,41 @@ Java_hdf_hdf5lib_H5_H5Rcreate
     jbyte      *refP;
     jboolean    isCopy2;
 
-    PIN_JAVA_STRING(name, rName, -1);
-
-    if (ref == NULL) {
-        UNPIN_JAVA_STRING(name, rName);
-        h5nullArgument( env, "H5Rcreate:  ref is NULL");
-    } /* end if */
-    else {
-        if ((ref_type == H5R_OBJECT) && ENVPTR->GetArrayLength(ENVPAR ref) != H5R_OBJ_REF_BUF_SIZE) {
-            UNPIN_JAVA_STRING(name, rName);
-            h5badArgument( env, "H5Rcreate:  ref input array != H5R_OBJ_REF_BUF_SIZE");
+    PIN_JAVA_STRING(name, rName);
+    if (rName != NULL) {
+        if (ref == NULL) {
+            h5nullArgument( env, "H5Rcreate:  ref is NULL");
         } /* end if */
-        else if ((ref_type == H5R_DATASET_REGION) && ENVPTR->GetArrayLength(ENVPAR ref) != H5R_DSET_REG_REF_BUF_SIZE) {
-            UNPIN_JAVA_STRING(name, rName);
-            h5badArgument( env, "H5Rcreate:  region ref input array != H5R_DSET_REG_REF_BUF_SIZE");
-        } /* end else if */
-        else if ((ref_type != H5R_OBJECT) && (ref_type != H5R_DATASET_REGION)) {
-            UNPIN_JAVA_STRING(name, rName);
-            h5badArgument( env, "H5Rcreate:  ref_type unknown type ");
-        } /* end else if */
         else {
-            refP = (jbyte*)ENVPTR->GetByteArrayElements(ENVPAR ref, &isCopy2);
-            if (refP == NULL) {
-                UNPIN_JAVA_STRING(name, rName);
-                h5JNIFatalError(env,  "H5Rcreate:  ref not pinned");
+            if ((ref_type == H5R_OBJECT) && ENVPTR->GetArrayLength(ENVPAR ref) != H5R_OBJ_REF_BUF_SIZE) {
+                h5badArgument( env, "H5Rcreate:  ref input array != H5R_OBJ_REF_BUF_SIZE");
             } /* end if */
+            else if ((ref_type == H5R_DATASET_REGION) && ENVPTR->GetArrayLength(ENVPAR ref) != H5R_DSET_REG_REF_BUF_SIZE) {
+                h5badArgument( env, "H5Rcreate:  region ref input array != H5R_DSET_REG_REF_BUF_SIZE");
+            } /* end else if */
+            else if ((ref_type != H5R_OBJECT) && (ref_type != H5R_DATASET_REGION)) {
+                h5badArgument( env, "H5Rcreate:  ref_type unknown type ");
+            } /* end else if */
             else {
-                status = H5Rcreate(refP, (hid_t)loc_id, rName, (H5R_type_t)ref_type, (hid_t)space_id);
-
-                UNPIN_JAVA_STRING(name, rName);
-                if (status < 0) {
-                    ENVPTR->ReleaseByteArrayElements(ENVPAR ref, refP, JNI_ABORT);
-                    h5libraryError(env);
+                refP = (jbyte*)ENVPTR->GetByteArrayElements(ENVPAR ref, &isCopy2);
+                if (refP == NULL) {
+                    h5JNIFatalError(env,  "H5Rcreate:  ref not pinned");
                 } /* end if */
                 else {
-                    ENVPTR->ReleaseByteArrayElements(ENVPAR ref, refP, 0);
+                    status = H5Rcreate(refP, (hid_t)loc_id, rName, (H5R_type_t)ref_type, (hid_t)space_id);
+
+                    if (status < 0) {
+                        ENVPTR->ReleaseByteArrayElements(ENVPAR ref, refP, JNI_ABORT);
+                        h5libraryError(env);
+                    } /* end if */
+                    else {
+                        ENVPTR->ReleaseByteArrayElements(ENVPAR ref, refP, 0);
+                    } /* end else */
                 } /* end else */
             } /* end else */
         } /* end else */
-    } /* end else */
+        UNPIN_JAVA_STRING(name, rName);
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Rcreate */
diff --git a/java/src/jni/h5tImp.c b/java/src/jni/h5tImp.c
index 55e16f8..1467b41 100644
--- a/java/src/jni/h5tImp.c
+++ b/java/src/jni/h5tImp.c
@@ -43,17 +43,18 @@ JNIEXPORT jlong JNICALL
 Java_hdf_hdf5lib_H5__1H5Topen2
     (JNIEnv *env, jclass clss, jlong loc_id, jstring name, jlong access_plist)
 {
-    hid_t       status;
+    hid_t       status = -1;
     const char *tName;
 
-    PIN_JAVA_STRING(name, tName, -1);
+    PIN_JAVA_STRING(name, tName);
+    if (tName != NULL) {
+        status = H5Topen2((hid_t)loc_id, tName, (hid_t)access_plist);
 
-    status = H5Topen2((hid_t)loc_id, tName, (hid_t)access_plist);
+        UNPIN_JAVA_STRING(name, tName);
 
-    UNPIN_JAVA_STRING(name, tName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jlong)status;
 } /* end Java_hdf_hdf5lib_H5__1H5Topen2 */
@@ -789,14 +790,15 @@ Java_hdf_hdf5lib_H5_H5Tget_1member_1index
     const char *tName;
     int         index = -1;
 
-    PIN_JAVA_STRING(field_name, tName, -1);
+    PIN_JAVA_STRING(field_name, tName);
+    if (tName != NULL) {
+        index = H5Tget_member_index((hid_t)type_id, tName);
 
-    index = H5Tget_member_index((hid_t)type_id, tName);
+        UNPIN_JAVA_STRING(field_name, tName);
 
-    UNPIN_JAVA_STRING(field_name, tName);
-
-    if (index < 0)
-        h5libraryError(env);
+        if (index < 0)
+            h5libraryError(env);
+    }
 
     return (jint)index;
 } /* end Java_hdf_hdf5lib_H5_H5Tget_1member_1index */
@@ -858,17 +860,18 @@ JNIEXPORT jint JNICALL
 Java_hdf_hdf5lib_H5_H5Tinsert
     (JNIEnv *env, jclass clss, jlong type_id, jstring name, jlong offset, jlong field_id)
 {
-    herr_t      status;
+    herr_t      status = -1;
     const char *tName;
     long        off = (long)offset;
 
-    PIN_JAVA_STRING(name, tName, -1);
+    PIN_JAVA_STRING(name, tName);
+    if (tName != NULL) {
+        status = H5Tinsert((hid_t)type_id, tName, (size_t)off, field_id);
 
-    status = H5Tinsert((hid_t)type_id, tName, (size_t)off, field_id);
-
-    UNPIN_JAVA_STRING(name,tName);
-    if (status < 0)
-        h5libraryError(env);
+        UNPIN_JAVA_STRING(name,tName);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Tinsert */
@@ -939,14 +942,15 @@ Java_hdf_hdf5lib_H5_H5Tset_1tag
     herr_t      status = -1;
     const char *tagP;
 
-    PIN_JAVA_STRING(tag, tagP, -1);
+    PIN_JAVA_STRING(tag, tagP);
+    if (tagP != NULL) {
+        status = H5Tset_tag((hid_t)type, tagP);
 
-    status = H5Tset_tag((hid_t)type, tagP);
+        UNPIN_JAVA_STRING(tag,tagP);
 
-    UNPIN_JAVA_STRING(tag,tagP);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 
     return (jint)status;
 } /* end Java_hdf_hdf5lib_H5_H5Tset_1tag */
@@ -1029,21 +1033,22 @@ Java_hdf_hdf5lib_H5_H5Tenum_1insert_1int
         h5nullArgument(env, "H5Tenum_insert:  value is NULL");
     } /* end if */
     else {
-        PIN_JAVA_STRING(name, nameP, -1);
-
-        intP = ENVPTR->GetIntArrayElements(ENVPAR value, &isCopy2);
-        if (intP == NULL) {
-            h5JNIFatalError(env, "H5Tenum_insert:  value not pinned");
-        } /* end if */
-        else {
-            status = H5Tenum_insert((hid_t)type_id, nameP, intP);
+        PIN_JAVA_STRING(name, nameP);
+        if (nameP != NULL) {
+            intP = ENVPTR->GetIntArrayElements(ENVPAR value, &isCopy2);
+            if (intP == NULL) {
+                h5JNIFatalError(env, "H5Tenum_insert:  value not pinned");
+            } /* end if */
+            else {
+                status = H5Tenum_insert((hid_t)type_id, nameP, intP);
 
-            ENVPTR->ReleaseIntArrayElements(ENVPAR value, intP, JNI_ABORT);
+                ENVPTR->ReleaseIntArrayElements(ENVPAR value, intP, JNI_ABORT);
 
-            if (status < 0)
-                h5libraryError(env);
-        } /* end else */
-        UNPIN_JAVA_STRING(name, nameP);
+                if (status < 0)
+                    h5libraryError(env);
+            } /* end else */
+            UNPIN_JAVA_STRING(name, nameP);
+        }
     } /* end else */
 
     return (jint)status;
@@ -1067,21 +1072,22 @@ Java_hdf_hdf5lib_H5_H5Tenum_1insert
         h5nullArgument(env, "H5Tenum_insert:  value is NULL");
     } /* end if */
     else {
-        PIN_JAVA_STRING0(name, nameP);
-
-        byteP = ENVPTR->GetByteArrayElements(ENVPAR value, &isCopy2);
-        if (byteP == NULL) {
-            h5JNIFatalError(env, "H5Tenum_insert:  value not pinned");
-        } /* end if */
-        else {
-            status = H5Tenum_insert((hid_t)type_id, nameP, byteP);
+        PIN_JAVA_STRING(name, nameP);
+        if (nameP != NULL) {
+            byteP = ENVPTR->GetByteArrayElements(ENVPAR value, &isCopy2);
+            if (byteP == NULL) {
+                h5JNIFatalError(env, "H5Tenum_insert:  value not pinned");
+            } /* end if */
+            else {
+                status = H5Tenum_insert((hid_t)type_id, nameP, byteP);
 
-            ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, JNI_ABORT);
+                ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, JNI_ABORT);
 
-            if (status < 0)
-                h5libraryError(env);
-        } /* end else */
-        UNPIN_JAVA_STRING(name, nameP);
+                if (status < 0)
+                    h5libraryError(env);
+            } /* end else */
+            UNPIN_JAVA_STRING(name, nameP);
+        }
     } /* end else */
 } /* end Java_hdf_hdf5lib_H5_H5Tenum_1insert */
 
@@ -1218,23 +1224,24 @@ Java_hdf_hdf5lib_H5_H5Tenum_1valueof_1int
         h5nullArgument(env, "H5Tenum_valueof:  value is NULL");
     } /* end if */
     else {
-        PIN_JAVA_STRING(name, nameP, -1);
-
-        intP = ENVPTR->GetIntArrayElements(ENVPAR value, &isCopy2);
-        if (intP == NULL)  {
-            h5JNIFatalError(env, "H5Tenum_valueof:  value not pinned");
-        } /* end if */
-        else {
-            status = H5Tenum_valueof((hid_t)type_id, nameP, intP);
-
-            if (status < 0) {
-                ENVPTR->ReleaseIntArrayElements(ENVPAR value, intP, JNI_ABORT);
-                h5libraryError(env);
+        PIN_JAVA_STRING(name, nameP);
+        if (nameP != NULL) {
+            intP = ENVPTR->GetIntArrayElements(ENVPAR value, &isCopy2);
+            if (intP == NULL)  {
+                h5JNIFatalError(env, "H5Tenum_valueof:  value not pinned");
             } /* end if */
-            else
-                ENVPTR->ReleaseIntArrayElements(ENVPAR value, intP, 0);
-        } /* end else */
-        UNPIN_JAVA_STRING(name, nameP);
+            else {
+                status = H5Tenum_valueof((hid_t)type_id, nameP, intP);
+
+                if (status < 0) {
+                    ENVPTR->ReleaseIntArrayElements(ENVPAR value, intP, JNI_ABORT);
+                    h5libraryError(env);
+                } /* end if */
+                else
+                    ENVPTR->ReleaseIntArrayElements(ENVPAR value, intP, 0);
+            } /* end else */
+            UNPIN_JAVA_STRING(name, nameP);
+        }
     } /* end else */
 
     return (jint)status;
@@ -1258,23 +1265,24 @@ Java_hdf_hdf5lib_H5_H5Tenum_1valueof
         h5nullArgument(env, "H5Tenum_valueof:  value is NULL");
     } /* end if */
     else {
-        PIN_JAVA_STRING0(name, nameP);
-
-        byteP = ENVPTR->GetByteArrayElements(ENVPAR value, &isCopy2);
-        if (byteP == NULL)  {
-            h5JNIFatalError(env, "H5Tenum_valueof:  value not pinned");
-        } /* end if */
-        else {
-            status = H5Tenum_valueof((hid_t)type_id, nameP, byteP);
-
-            if (status < 0) {
-                ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, JNI_ABORT);
-                h5libraryError(env);
+        PIN_JAVA_STRING(name, nameP);
+        if (nameP != NULL) {
+            byteP = ENVPTR->GetByteArrayElements(ENVPAR value, &isCopy2);
+            if (byteP == NULL)  {
+                h5JNIFatalError(env, "H5Tenum_valueof:  value not pinned");
             } /* end if */
-            else
-                ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, 0);
-        } /* end else */
-        UNPIN_JAVA_STRING(name, nameP);
+            else {
+                status = H5Tenum_valueof((hid_t)type_id, nameP, byteP);
+
+                if (status < 0) {
+                    ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, JNI_ABORT);
+                    h5libraryError(env);
+                } /* end if */
+                else
+                    ENVPTR->ReleaseByteArrayElements(ENVPAR value, byteP, 0);
+            } /* end else */
+            UNPIN_JAVA_STRING(name, nameP);
+        }
     } /* end else */
 } /* end Java_hdf_hdf5lib_H5_H5Tenum_1valueof */
 
@@ -1487,14 +1495,15 @@ Java_hdf_hdf5lib_H5_H5Tcommit
     herr_t      status = -1;
     const char *tName;
 
-    PIN_JAVA_STRING0(name, tName);
+    PIN_JAVA_STRING(name, tName);
+    if (tName != NULL) {
+        status = H5Tcommit2((hid_t)loc_id, tName, (hid_t)type, (hid_t)link_plist_id, (hid_t)create_plist_id, (hid_t)access_plist_id);
 
-    status = H5Tcommit2((hid_t)loc_id, tName, (hid_t)type, (hid_t)link_plist_id, (hid_t)create_plist_id, (hid_t)access_plist_id);
+        UNPIN_JAVA_STRING(name, tName);
 
-    UNPIN_JAVA_STRING(name, tName);
-
-    if (status < 0)
-        h5libraryError(env);
+        if (status < 0)
+            h5libraryError(env);
+    }
 } /* end Java_hdf_hdf5lib_H5_H5Tcommit */
 
 /*
diff --git a/java/src/jni/h5util.c b/java/src/jni/h5util.c
index f9bd291..acf57c8 100644
--- a/java/src/jni/h5util.c
+++ b/java/src/jni/h5util.c
@@ -2634,49 +2634,50 @@ Java_hdf_hdf5lib_H5_H5export_1dataset
         h5nullArgument(env, "HDF5Library_export_data:  object_path is NULL");
     } /* end else if */
     else {
-        PIN_JAVA_STRING0(file_name, fileName);
+        PIN_JAVA_STRING(file_name, fileName);
+        if (fileName != NULL) {
+            file_id = H5Fopen(fileName, (unsigned)H5F_ACC_RDWR, (hid_t)H5P_DEFAULT);
 
-        file_id = H5Fopen(fileName, (unsigned)H5F_ACC_RDWR, (hid_t)H5P_DEFAULT);
+            UNPIN_JAVA_STRING(file_name, fileName);
 
-        UNPIN_JAVA_STRING(file_name, fileName);
-
-        if (file_id < 0) {
-            /* throw exception */
-            h5libraryError(env);
-        } /* end if */
-        else {
-            object_name = ENVPTR->GetStringUTFChars(ENVPAR object_path, &isCopy2);
-            if (object_name == NULL) {
-                h5JNIFatalError( env, "H5Dopen:  object name not pinned");
+            if (file_id < 0) {
+                /* throw exception */
+                h5libraryError(env);
             } /* end if */
             else {
-                dataset_id = H5Dopen2(file_id, object_name, H5P_DEFAULT);
-
-                ENVPTR->ReleaseStringUTFChars(ENVPAR object_path, object_name);
-
-                if (dataset_id < 0) {
-                    H5Fclose(file_id);
-                    h5libraryError(env);
+                object_name = ENVPTR->GetStringUTFChars(ENVPAR object_path, &isCopy2);
+                if (object_name == NULL) {
+                    h5JNIFatalError( env, "H5Dopen:  object name not pinned");
                 } /* end if */
                 else {
-                    file_export = ENVPTR->GetStringUTFChars(ENVPAR file_export_name, 0);
-                    stream = HDfopen(file_export, "w+");
-                    ENVPTR->ReleaseStringUTFChars(ENVPAR file_export_name, file_export);
+                    dataset_id = H5Dopen2(file_id, object_name, H5P_DEFAULT);
 
-                    ret_val = h5str_dump_simple_dset(stream, dataset_id, binary_order);
+                    ENVPTR->ReleaseStringUTFChars(ENVPAR object_path, object_name);
 
-                    if (stream)
-                        HDfclose(stream);
+                    if (dataset_id < 0) {
+                        H5Fclose(file_id);
+                        h5libraryError(env);
+                    } /* end if */
+                    else {
+                        file_export = ENVPTR->GetStringUTFChars(ENVPAR file_export_name, 0);
+                        stream = HDfopen(file_export, "w+");
+                        ENVPTR->ReleaseStringUTFChars(ENVPAR file_export_name, file_export);
 
-                    H5Dclose(dataset_id);
+                        ret_val = h5str_dump_simple_dset(stream, dataset_id, binary_order);
 
-                    H5Fclose(file_id);
+                        if (stream)
+                            HDfclose(stream);
 
-                    if (ret_val < 0)
-                        h5libraryError(env);
+                        H5Dclose(dataset_id);
+
+                        H5Fclose(file_id);
+
+                        if (ret_val < 0)
+                            h5libraryError(env);
+                    } /* end else */
                 } /* end else */
             } /* end else */
-        } /* end else */
+        }
     } /* end else */
 } /* end Java_hdf_hdf5lib_H5_H5export_1dataset */
 
diff --git a/java/test/CMakeLists.txt b/java/test/CMakeLists.txt
index 27f1903..8cb41f7 100644
--- a/java/test/CMakeLists.txt
+++ b/java/test/CMakeLists.txt
@@ -88,7 +88,11 @@ set (CMAKE_JAVA_CLASSPATH "${CMAKE_JAVA_CLASSPATH}${CMAKE_JAVA_INCLUDE_FLAG_SEP}
 set (testfilter "OK (598 tests)")
 
 if (CMAKE_BUILD_TYPE MATCHES Debug)
-  set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+  if (WIN32)
+    set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_D;")
+  else()
+    set (CMD_ARGS "-Dhdf.hdf5lib.H5.loadLibraryName=hdf5_java_debug;")
+  endif()
 endif(CMAKE_BUILD_TYPE MATCHES Debug)
 
 add_test (