Error: Non-array passed to JNI array operations

Question

Can anyone see what I am doing wrong? I am trying to go through the array of objects example in the online JNI text book "The Java Native Interface Programmer's Guide and Specification" by Sheng Liang. The book and pertinent chapter can be found here:
http://java.sun.com/docs/books/jni/html/objtypes.html#27791
The error I received on running the program with the -Xcheck:jni switch is this:
FATAL ERROR in native method: Non-array passed to JNI array operations
     at petes.JNI.ObjectArrayTest.initInt2DArray(Native Method)
     at petes.JNI.ObjectArrayTest.main(ObjectArrayTest.java:14)Without the xcheck switch, I get a huge error log file that I can reproduce here if needed.
My c code with #ifdef _Debug statements removed for readability is listed below.  The location of the error (I believe) is marked:
#include <jni.h>
#include <stdio.h>
#include "petes_JNI_ObjectArrayTest.h"
//#define _Debug
// error found running the program with the -Xcheck:jni switch
//page 38 and 39 of The Java Native Interface Guide by Sheng Liang
JNIEXPORT jobjectArray JNICALL Java_petes_JNI_ObjectArrayTest_initInt2DArray
  (JNIEnv *env, jclass class, jint size)
     jobjectArray result;
     jint i;
     jclass intArrCls = (*env)->FindClass(env, "[I");
     if (intArrCls == NULL)
          return NULL;
     result = (*env)->NewObjectArray(env, size, intArrCls, NULL);
     if (result = NULL)
          return NULL; 
     for (i = 0; i < size; i++)
          jint tmp[256]; // make sure it is large enough
          jint j;
          jintArray iarr = (*env)->NewIntArray(env, size);
          if (iarr == NULL)
               return NULL; 
          for (j = 0; j < size; j++)
               tmp[j] = i + j;
          (*env)->SetIntArrayRegion(env, iarr, 0, size, tmp);
          (*env)->SetObjectArrayElement(env, result, i, iarr); // ***** ERROR:  Non-array passed to JNI array operations
          (*env)->DeleteLocalRef(env, iarr);
     return result;
}Here is my java code
package petes.JNI;
public class ObjectArrayTest
    private static native int[][] initInt2DArray(int size);
    static
        System.loadLibrary("petes_JNI_ObjectArrayTest");
    public static void main(String[] args)
        int[][] i2arr = initInt2DArray(3);
        if (i2arr != null)
            for (int i = 0; i < i2arr.length; i++)
                for (int j = 0; j < i2arr[0].length; j++)
                    System.out.println(" " + i2arr[i][j]);
                System.out.println();
        else
            System.out.println("i2arr is null");
}Thanks in advance!
Pete

Answer 1

Niceguy1: Thanks for the quick reply!
So far, I mainly see the usual differences between C and C++ JNI calls. Also, in the example you gave, they use a lot of casts, but that doesn't seem to make much difference to my output. Also, in the example, they create a 0-initilized int array, and use this class to initialze the class type of the Object array. I get the class type by a call to FindClass for a class type of "[I".  I'll try this their way and see what happens...
Edit:  Changing the way I find the array element Object type did not help.  I still get the same error as previous.  Any other ideas would be greatly appreciated.
Message was edited by:
        petes1234