Deadlock in Java ( AI Generated )

Deadlock:

Deadlock occurs in a multithreaded program when two or more threads are unable to make progress because each thread is waiting for a resource that is held by another thread, creating a cycle of dependencies. This situation can happen in scenarios where multiple locks are involved.

Example:

java
class DeadlockExample {
    private final Object lock1 = new Object();
    private final Object lock2 = new Object();

    public void method1() {
        synchronized (lock1) {
            System.out.println("Thread 1: Holding lock1...");
            synchronized (lock2) {
                System.out.println("Thread 1: Holding lock1 and lock2...");
            }
        }
    }

    public void method2() {
        synchronized (lock2) {
            System.out.println("Thread 2: Holding lock2...");
            synchronized (lock1) {
                System.out.println("Thread 2: Holding lock2 and lock1...");
            }
        }
    }
}

public class Main {
    public static void main(String[] args) {
        DeadlockExample example = new DeadlockExample();

        Thread t1 = new Thread(example::method1);
        Thread t2 = new Thread(example::method2);

        t1.start();
        t2.start();
    }
}

Key Points:

• Mutual Exclusion: Threads need exclusive access to shared resources.
• Hold and Wait: Threads hold one resource while waiting for another.
• No Preemption: Resources cannot be forcibly taken from threads.
• Circular Wait: A cycle of dependencies exists among threads.

Avoiding Deadlocks:

1. Avoid Nested Locks: Minimize the use of multiple locks.
2. Lock Ordering: Always acquire locks in a consistent order.
3. Timeouts: Use timeouts while trying to acquire locks.
4. Deadlock Detection: Implement mechanisms to detect and resolve deadlocks.

( Content provided with the assistance of ChatGPT, an AI model by OpenAI )