We have some old code that I am taking over and we have this.

JNIEXPORT jint JNICALL
Java_com_ibm_jusb_os_windows_JavaxUsb_submitControlPipeRequest
(JNIEnv *env, ..., jbyteArray buffer, ... )
{
...
       output = (*env)->GetByteArrayElements(env, jbOutBuffer, 0);//Get the
pointer to jbyteArray
...

}

Is it necessary to call
if(output) (*env)->ReleaseByteArrayElements(env, jbOutBuffer, output, 0);