DeadLock.java

package ThreadTest.others;


/* add sleep will hugely increase the possibilities of dead lock */

import static java.lang.Thread.sleep;

public class DeadLock {
    public static void main(String[] args) {
        StringBuffer s1 = new StringBuffer();
        StringBuffer s2 = new StringBuffer();

        new Thread(){
            @Override
            public void run() {
                synchronized (s1){
                    s1.append("a");
                    s2.append(1);

                    try {
                        sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    synchronized (s2){
                        s1.append("b");
                        s2.append(2);
                    }

                    System.out.println(s1);
                    System.out.println(s2);
                }
            }
        }.start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (s2){
                    s1.append("c");
                    s2.append(3);

                    try {
                        sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    synchronized (s1){
                        s1.append("d");
                        s2.append(4);
                    }
                    System.out.println(s1);
                    System.out.println(s2);
                }
            }
        }).start();
    }
}