Java HotSpot Virtual Machine

Hello,

I'm learning JNI, and I have a need to pass a dynamic array created in C++ back to java. Here's the basic relevant code

// C++ CODE //
JNIEXPORT jint JNICALL
Java_plotkdtree_kdtreeCinterface_CreateKDtree(JNIEnv *env, jobject obj, jintArray leafIndices)
{

     jint* jleafIndices;

     //Dynamically Create Arrays
     jleafIndices = new jint[numPts];
     leafIndices = env->NewIntArray(numPts);
            if(leafIndices == NULL || jleafIndices == NULL) {
                  cout << "Error: leafIndices did not allocate properly....exiting\n";
                  exit(1);
       }

     //Assign values to Array jleafIndices 
    int numLeafs=0;
    for(int i=0; i < myTree.nboxes; i++) 
        if(myTree.boxes.dau1 == 0 && myTree.boxes[i].dau2 == 0)

jleafIndices[numLeafs++] = i;

//Copy local array leafIndices into JAVA array leafIndices

env->SetIntArrayRegion(leafIndices,0,numLeafs,jleafIndices);



//Clean up Memory

delete [] jleafIndices;

jleafIndices = NULL;

env->DeleteLocalRef(leafIndices);

}


and my java file
public class kdtreeCinterface extends JComponent {

private static int leafIndices[];

private static int numLeafs; //Assigned value in C++ Code





// This tells Java to load the C++ library "kdtreeC".

static{

System.loadLibrary("kdtreeC");

}





// This creates a component for our C++ Method.

private native int CreateKDtree(int[] leafIndices);



//Create function to call C routines

public int callKDTree() {

CreateKDtree(leafIndices); 





System.out.println(numLeafs);

//leafIndices = new int[numLeafs]; //NOTE

System.out.print("leafIndices equals:\n");

for(int i=0;i<numLeafs;i++) {

System.out.print(leafIndices[i]);

System.out.print("\n");

}



return 0;

}

}
I'm guessing the problem may have something to do with how my array is initialized in JAVA.  With the line with "//NOTE" next to it commented out, the program crashes, with it uncommented, it prints all zeros.  Where/How do I initialize this array?  And does the rest of the code look fine?

Thanks, i'm new to both JAVA and JNI, your help is greatly appreciated

Edited by: moddinati on Jun 17, 2008 3:11 PM