Passing a byte[] in Java to a function in C through JNI: how to use jarraybyte

you can get jbyte* by GetByteArrayElements:

jbyte* bufferPtr = (*env)->GetByteArrayElements(env, array, NULL);

And it is important to know the length of your array:

jsize lengthOfArray = (*env)->GetArrayLength(env, array);

Having jbyte* and length, you can do all the things in c-array. Finally, releasing it:

(*env)->ReleaseByteArrayElements(env, array, bufferPtr, 0);