class  X  implements  Runnable {
Runnable r =  null ;
  public  X (Runnable iface){
  this .r = iface;
}
  public   void  run(){
...
  if  (r !=  null ) r.callme();
...
 }
  public   void  callme(){
...  do  something
 }
}


{
 Runnable run1 =  new  X( null );
 Runnable run2 =  new  X(run1);
 
 Thread thread1 =  new  Thread(run1);
 Thread thread2 =  new  Thread(run2);
 
 thread1.start();
 thread2.start();
}

 import  java.util.concurrent.locks.*;

 public   class  ThreadsSample {
     public   static   void  main(String args[]){

         new  Thread( new  ProcessorThread()).start();
         new  Thread( new  DrawerThread()).start();
    }
    
     private   static   boolean  ready = false;
     private   static   double  data = 0d;
     private   static  Lock readyLock =  new  ReentrantLock();
    
    
     public   static   void  putData( double  number){
        System.out.println("I received " + number + " and ready to proceed");
        readyLock.lock();
         try {
            ready = true;
            data = number;
        }  finally  {
          readyLock.unlock();
        }
    }
    
     public   static   boolean  getReady(){
        readyLock.lock();
         try {
             return  ready;
        }  finally  {
          readyLock.unlock();
        }
    }
    
     public   static   double  getData(){
        readyLock.lock();
         try {
            ready = false;
             return  data;
        }  finally  {
          readyLock.unlock();
        }
    }

}

 class  ProcessorThread  implements  Runnable {
     public   void  run(){
         try {
             while  (true) {
                ThreadsSample.putData(Math.random());
                Thread.sleep( 1000 );
            }
        }  catch  (InterruptedException e){
            e.printStackTrace();
        }
    }
}

 class  DrawerThread  implements  Runnable {
     public   void  run(){
         try {
             while  (true) {
                 if  (ThreadsSample.getReady()) {
                     double  data = ThreadsSample.getData();
                    System.out.println("We got something new :) = " + data);
                }
                Thread.sleep( 300 );
            }
        }  catch  (InterruptedException e){
            e.printStackTrace();
        }
    }
}