How do the atomic package classes as AtomicInteger etc work

Question

I have read that using atomic package classes enables us to do thread safe,lock less coding. But I am not very sure about how do the methods in the classes of atomic package

Answer 1

They use very low level instructions such as Compare and Swap, and multiple other methods from sun.misc.Unsafe class.

Basically, a method call like compareAndSwap() will correspond to a unique processor instruction, which remove a lot of multithreading issues.