What thread synchronization methods and mechanisms do you know in Java?

In Java, the following main methods and mechanisms are used for thread synchronization:

• Keyword synchronized — locking methods or code blocks to ensure mutual exclusion.
• Object methods wait(), notify(), notifyAll() — for organizing interaction between threads through monitors.
• Classes from the java.util.concurrent package:
  • ReentrantLock — a more flexible lock with the ability to attempt to acquire and set timeouts.
  • Semaphore — to limit the number of threads executing a certain section of code simultaneously.
  • CountDownLatch, CyclicBarrier — for coordinating the start or completion of threads.
  • ConcurrentHashMap, BlockingQueue — thread-safe collections.
• Atomic classes from java.util.concurrent.atomic — for lock-free operations, e.g., AtomicInteger.

Example of using synchronized:

public class Counter {
    private int count = 0;

    public synchronized void increment() {
        count++;
    }

    public synchronized int getCount() {
        return count;
    }
}

This approach guarantees that changes to the variable count are atomic and visible to all threads.