DeadLockTest.java

package test;

/**
 * DeadLockTest
 *
 * @author Eugene Matyushkin
 * @version 1.0
 */
public class DeadLockTest
{

    public static void main(String[] args)
    {
        A a1 = new A();
        A a2 = new A();
        Thread t1 = new Thread(new Tester(a1, a2));
        Thread t2 = new Thread(new Tester(a2, a1));
        t1.start();
        t2.start();
    }

    public static class Tester implements Runnable
    {

        static int nextId = 1;

        private A obj1;
        private A obj2;
        private int id = 0;

        public Tester(A obj1, A obj2)
        {
            this.obj1 = obj1;
            this.obj2 = obj2;
            id = nextId++;
        }

        public void run()
        {
            print("Setting value to obj1... ");
            obj1.setValue(id);
            print("done.");
            print("value of obj1: " + obj1.getValue());
            print("Comparing objects... ");
            print("Done. Result: " + ((obj1.equals(obj2)) ? "equal" : "not equal"));
        }

        private void print(String msg)
        {
            System.out.println("Thread #" + id + ": " + msg);
        }
    }

    public static class A
    {

        private int value = 0;

        synchronized void setValue(int value)
        {
            this.value = value;
        }

        synchronized int getValue()
        {
            return value;
        }

        public synchronized boolean equals(Object o)
        {
            A a = (A) o;
            try
            {
                Thread.sleep(1000);
            }
            catch (InterruptedException ex)
            {
                System.err.println("Interrupted!");
            }
            return value == a.getValue();
        }
    }
}