SynchronizedBlock.java

class CallMe2 {
     void call(String msg) {
        System.out.print("[" + msg);
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            System.out.println("Interrupted");
        }
        System.out.println("]");
    }
}

class Caller2 implements Runnable {
    String msg;
    CallMe2 target;
    Thread t;

    public Caller2(CallMe2 c, String s) {
        target = c;
        msg = s;
        t = new Thread(this);
        t.start();
    }

    public void run() {
        synchronized (target) {
            target.call(msg);
        }
    }
}

public class SynchronizedBlock {
    public static void main(String[] args) {
        CallMe2 target = new CallMe2();
        Caller2 ob1 = new Caller2(target, "Hello");
        Caller2 ob2 = new Caller2(target, "Synchronized");
        Caller2 ob3 = new Caller2(target, "World");
    }
}