public class Watek extends Thread {
boolean running;
Object synchObj;
	public Watek() {
		running = true;
		synchObj = new Object();
	}

	

	 public void run() {
	    while (running) {
	      synchronized (synchObj) {
	         try {
	        	 show('A');
	            synchObj.wait();
	         } catch (InterruptedException e) {
	             // error handling
	         }
	      }
	    }
	 }

	 public static void  show(char c){
		 System.out.println(c);
	 }
	 public void shutdown() {
	    running = false;
	    synchronized (synchObj) {
	        synchObj.notify();
	    }
	 }
	 public static void main(String[] args){
		 Watek w = new Watek();
		 w.start();
	 }
}