What tools for synchronization are available in Java?

In Java, the following tools are used for thread synchronization and managing access to shared resources:

• Keyword synchronized — blocks or methods that provide exclusive access to code.
• Classes from the java.util.concurrent.locks package:
  • ReentrantLock — a more flexible alternative to synchronized with the ability to attempt lock acquisition and timeout.
  • ReadWriteLock — separates lock into read and write, allowing multiple threads to read simultaneously.
• Semaphores (Semaphore) — limit the number of threads executing a certain section of code at the same time.
• Barrier synchronizations (CyclicBarrier, CountDownLatch) — allow threads to wait for each other at certain points.
• Atomic classes (AtomicInteger, AtomicReference, etc.) — provide atomic operations without locks.

Example of using ReentrantLock:

import java.util.concurrent.locks.ReentrantLock;

ReentrantLock lock = new ReentrantLock();

lock.lock();
try {
    // critical section
} finally {
    lock.unlock();
}