Example Deadlock

public class DeadLockDanger {

    String o1 = "Lock " ;                        // (1)
    String o2 = "Step ";                         // (2)

    Thread t1 = (new Thread("Printer1") {        // (3)
        public void run() {
            while(true) {
                synchronized(o1) {               // (4)
                    synchronized(o2) {           // (5)
                        System.out.println(o1 + o2);
                    }
                }
            }
        }
    });

    Thread t2 = (new Thread("Printer2") {        // (6)
        public void run() {
            while(true) {
                synchronized(o2) {               // (7)
                    synchronized(o1) {           // (8)
                        System.out.println(o2 + o1);
                    }
                }
            }
        }
    });

    public static void main(String[] args) {
        DeadLockDanger dld = new DeadLockDanger();
        dld.t1.start();
        dld.t2.start();
    }
}

Possible output from the program:

...
Step Lock
Step Lock
Lock Step
Lock Step
Lock Step
...