$RESPONSE is a reference and it is basically a memory address

In interest of full-disclosure, it is not really a memory address, but basically like a memory address. I'm saying this for new-user benefit since MCS probably knows this. A reference is an entry in a symbol-table, if you like...not quite like C/C++ pointers. In Java, well, objects just act as references, so the line is blurred in a rather confusing way if that's where you are coming from.