java dead lock demo

DeadLockDemo.java

public class DeadLockDemo {
    public static void main(String[] args) {
        Object o1 = new Object();
        Object o2 = new Object();

        Runnable r1 = () -> {
            synchronized(o1) {
                try {
                    Thread.sleep(3000);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                synchronized(o2) {
                    System.out.println("in r1...");
                }
            }
        };

        Runnable r2 = () -> {
            synchronized(o2) {
                try {
                    Thread.sleep(3000);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                synchronized(o1) {
                    System.out.println("in r2...");
                }
            }
        };

        Thread t1 = new Thread(r1);
        Thread t2 = new Thread(r2);
        t1.start();
        t2.start();
        System.out.println("in main, ending...");
    }
}