Does declaring AtomicLong with the volatile keyword guarantee visibility of changes to other threads?

The AtomicLong class from the java.util.concurrent.atomic package already provides the necessary guarantees of visibility and atomicity of operations without the need to use the volatile keyword. Inside AtomicLong, a mechanism of low-level atomic operations is used, which guarantees that changes to the value will be visible to other threads immediately after they are performed.

Declaring AtomicLong with volatile does not add any additional guarantees and is generally unnecessary. volatile itself ensures the visibility of variable changes between threads but does not guarantee the atomicity of complex operations (e.g., increment). AtomicLong addresses both issues.

Example of using AtomicLong:

import java.util.concurrent.atomic.AtomicLong;

public class Counter {
    private AtomicLong count = new AtomicLong(0);

    public void increment() {
        count.incrementAndGet(); // atomic increment
    }

    public long getCount() {
        return count.get(); // guaranteed visibility
    }
}

Thus, it is sufficient to simply use AtomicLong without volatile for correct operation in a multithreaded environment.