Question

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Java: volatile boolean vs AtomicBoolean

When is it appropriate to use a volatile primitive (e.g. boolean, integer or long) instead of AtomicBoolean, AtomicInteger or AtomicLong, and vice-versa?

Answer 1

The visibility semantics are exactly the same, the situation where using the atomic primitives is useful is when you need to use their atomic methods.

For example:

if (volatileBoolean) {
    volatileBoolean = !volatileBoolean;
}

could create issues in a multi threaded environment as the variable could change between the two lines. If you need the test&assignment to be atomic, you can use:

atomicBoolean.compareAndSet(true, false);