Casting char * to jbytearray

Question

Hi all,
I had a urgent problem on casting char * to jbytearray. Can anyone help me out? Thank you very much in advance.
Assume I have char * which has the content I want to cast into jbytearray, then return this jbytearray to java applicaiton.
I did following code, char * buffer is already known:
jbyteArray bArray;
jbyte *byteArrayElement;
long length;
bArray = (*jenv)->NewIntArray(jenv,(jsize)length);
byteArrayElement =(jenv)->GetByteArrayElements(jenv,bArray, &isCopy);
for (i=0;i<length;i++){
byteArrayElement(i]=(jbyte)buffer(i];
if (isCopy == JNI_TRUE){
(*jenv)->ReleaseByteArrayElements(jenv,bArray, byteArrayElement, 0);
return bArray;
The error always shows as follow:
An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : 11 occurred at PC=0x400BEE9C
Function=(null)+0x400BEE9C
Library=/lib/i686/libc.so.6
Trace down to the program, I found that this code cannot pass the last step of casting, which means:
(*jenv)->ReleaseByteArrayElements(jenv,bArray, (jbyte *)byteArrayElement, 0);
This line seems block the whole program, Any ideas?
Many Thanks
Rui

Answer 1

I think you need this:
jbyteArray bArray;
unsigned char * byteArrayElements;
long length;
bArray = (*jenv)->NewByteArray(jenv,(jsize)length);
byteArrayElements=(*jenv)->GetByteArrayElements(jenv,bArray,NULL);
for (i=0;i<length;i++)
    byteArrayElements=(jbyte)buffer[i];
// or better: memcpy(byteArrayElements,buffer,length);
(*jenv)->ReleaseByteArrayElements(jenv,bArray, byteArrayElements, 0);