What methods and approaches do you use to ensure security when developing multithreaded applications?

Several approaches are used to ensure safety in multithreaded applications:

• Synchronization of access to shared resources using the synchronized keyword, locks (Lock), atomic classes (AtomicInteger, AtomicReference, etc.).
• Avoiding state or using immutable objects to prevent data races.
• Using thread-safe collections from java.util.concurrent (e.g., ConcurrentHashMap).
• Proper management of thread lifecycle and using thread pools (ExecutorService).
• Avoiding deadlocks through careful design of lock acquisition order.

Example of using ReentrantLock:

Lock lock = new ReentrantLock();
lock.lock();
try {
    // critical section
} finally {
    lock.unlock();
}

These methods help prevent race conditions, ensure data integrity, and maintain application stability.