Thread synchronization block

Using  synchronized Block

class Callme {

void call(String msg) {

System.out.print("[" + msg);

try {

Thread.sleep(1000);

} catch (InterruptedException e) {

System.out.println("Interrupted");

}

System.out.println("]");

}

}

class Caller implements Runnable {

String msg;

Callme target;

Thread t;

public Caller(Callme targ, String s) {

target = targ;

msg = s;

t = new Thread(this);

t.start();

}

// synchronize calls to call()

public void run() {

synchronized(target) { // synchronized block

target.call(msg);

}

}

}

class Synch1 {

public static void main(String args[]) {

Callme target = new Callme();

Caller ob1 = new Caller(target, "Hello");

Caller ob2 = new Caller(target, "Synchronized");

Caller ob3 = new Caller(target, "World");

// wait for threads to end

try {

ob1.t.join();

ob2.t.join();

ob3.t.join();

} catch(InterruptedException e) {

System.out.println("Interrupted");

}

}

}