Pls explain the program

[Niyas Ahmed Sheikh]

class callme
{ 
  void call(String msg)
  {
    System.out.println("[" + msg);
    try
    {
       Thread.sleep(1000);
    }
    catch(InterruptedException e)
    {
       System.out.println("Interrupted in child");
    }
    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();
   }
   public void run()
   {
     target.call(msg);
   }
}
 
class sync
{
  public static void main(String args[])
  {
    callme target = new callme();
    [B]caller obj1 = new caller(target,"Hello");             
    caller obj2 = new caller(target,"Synchronised");             
    caller obj3 = new caller(target,"World"); [/B]            
  }
}

In the above, what will happened when we sending the 'target' object as argument. I can't understand the coding in BOLD. Please explain it, why the object has been send as argument and other related tips in this regd.

[Svend Rost]

You forgot to tell us, what happend when you ran the program.

Disclaimer: I havn't tested the program.

 
callme target = new callme();    
caller obj1 = new caller(target,"Hello");                 
caller obj2 = new caller(target,"Synchronised");                 
caller obj3 = new caller(target,"World");  

Your three caller objects gets initialized, and as you can see in their
constructor:

 
public caller(callme targ, String s)   
{     
 target = targ;     
 msg = s;    
 t = new Thread(this);     
 t.start();  
}
 

They start themselves as threads, and their run method gets called which
calls the callme object's call method, which prints "[message]" unless
it gets interupted by another thread..

/Svend Rost