Using one of these mechanisms:

- SetByteArrayRegion()

- use GetByteArrayElements(), modify the local copy using "normal"
 assignment, then use ReleaseByteArrayElements() to propagate your
 changes back to the Java array.

/gordon

Thanks guys, it works except for one thing....
The VM crashes!!!

This is the most interesting problem ever encountered.
I've tested each line one by one and after that
I've found out that the lines that are commented out
is the code that is causing the VM to crash

All the other code works perfectly. But the loop that
copies the contents of the buffer retrieved
by GetSample() (a method implemented by me)
into the jbyte array completely screws up everything

More interestingly, this method works for the first 2 invocations
if compiled with the for loop then crashes!

Compile w/o the loop method works perfectly

Im just as confused as you are

That loop is crucial because it is what fills the arrays!
Or is there a workaround?

Here's the code for it... it completely stumped me... any ideas are
highly appreciated!

JNIEXPORT jbyteArray JNICALL Java_SomeClass_readNextArray
 (JNIEnv *env, jobject obj)
{
   BYTE *buffer = NULL;
   DWORD bufferlen = 0;
   GetSample(&buffer, &bufferlen);
   jbyteArray bArray = env->NewByteArray( bufferlen );
   jbyte *jBytes = env->GetByteArrayElements( bArray, 0);
   //Problem Code!!!
   //for(DWORD i = 0; i < bufferlen; i++)    {
   //    jBytes[i] = buffer[i];
   //}
   env->ReleaseByteArrayElements( bArray, jBytes, 0);
   return bArray;
}

PROBLEM SOLVED!!!

I simply memcpy'd twice on some temporary BYTE*s then copy them into
jbyte using a for loop

BYTE* tempMem;
DWORD len = 0;
hr = inssBuffer->GetBufferAndLength(&tempMem, &len);
BYTE* tempMem2 = new BYTE[len];
jbyteArray bArray = env->NewByteArray( len);
jbyte *jBytes = env->GetByteArrayElements( bArray, 0);
if(hr == S_OK)    {
   memcpy(tempMem2, tempMem, len);
   for(DWORD i = 0; i < len; i++)    {
       jBytes[i] = tempMem2[i];
   }
}
//then clean up (cleanup code ommited for clarity
env->ReleaseByteArrayElements( bArray, jBytes, 0);
return bArray;

so now i am able to return the entire array

This works perfectly this time. Thanks for all who tried to help me.
It is very much appreciated - thaks for reminding me to put in
error-checking code and giving me some ways to test it out and giving
me tips

Thank you all again!