Deadlock Program

public class TestThread {
   public static Object Lock1 = new Object();
   public static Object Lock2 = new Object();
   
   public static void main(String args[]) {
      ThreadDemo1 T1 = new ThreadDemo1();
      ThreadDemo2 T2 = new ThreadDemo2();
      T1.start();
      T2.start();
   }
   
   private static class ThreadDemo1 extends Thread {
      public void run() {
         synchronized (Lock1) {
            System.out.println("Thread 1: Holding lock 1...");
            
            try { Thread.sleep(10); }
            catch (InterruptedException e) {}
            System.out.println("Thread 1: Waiting for lock 2...");
            
            synchronized (Lock2) {
               System.out.println("Thread 1: Holding lock 1 & 2...");
            }
         }
      }
   }
   private static class ThreadDemo2 extends Thread {
      public void run() {
         synchronized (Lock2) {
            System.out.println("Thread 2: Holding lock 2...");
            
            try { Thread.sleep(10); }
            catch (InterruptedException e) {}
            System.out.println("Thread 2: Waiting for lock 1...");
            
            synchronized (Lock1) {
               System.out.println("Thread 2: Holding lock 1 & 2...");
            }
         }
      }
   } 
}

Output

Thread 1: Holding lock 1...
Thread 2: Holding lock 2...
Thread 1: Waiting for lock 2...
Thread 2: Waiting for lock 1...

How to Avoid Deadlock in Java?
Deadlocks cannot be completely resolved. But we can avoid them by following basic rules
mentioned below:

1.Avoid Nested Locks: We must avoid giving locks to multiple threads, this is the main 
reason for a deadlock condition. It normally happens when you give locks to multiple threads.
2.Avoid Unnecessary Locks: The locks should be given to the important threads. 
Giving locks to the unnecessary threads that cause the deadlock condition.
3.Using Thread Join: A deadlock usually happens when one thread is waiting 
for the other to finish. In this case, we can use join with a maximum time that a thread

 will take.