Difference between getAndSet and compareAndSet in AtomicBoolean

Question

The thread title should be self-explnatory... I\'m a bit confused between the specification of below methos from AtomicBoolean class:

• java.u

Answer 1

The documentation is pretty clear.

• getAndSet --> "Atomically sets to the given value and returns the previous value."
• compareAndSet --> "Atomically sets the value to the given updated value if the current value == the expected value."

Not surprisingly, compareAndSet takes two arguments.

In your specific case:

• if (flag.getAndSet(false)) will set flag to false only if its previous value was true
• That would be the equivalent of if (flag.compareAndSet(true, false))