thread

[Barbara Nutter]

class t1 extends Thread
{
t1(Runnable runnable)
{ super(runnable);
}
public void run()
{ System.out.println("Hello");

}

}

class t2 implements Runnable
{ public void run()
{ System.out.println("Hello");
}
}

class t3
{ public static void main(String args[])
{ t2 T2=new T2();
t1 T1=new T1(T2);
T1.start();
}}
What should be the output..please explain?

[Les Morgan]

class t3{ 
  public static void main(String args[]){ 
//    t2 T2=new T2();  //create a new T2 this is an error because you should be creating a t2 object according to your code;
       T2 t2 = new T2();
//    t1 T1=new T1(T2);  //proper style has Class names capitalized
      T1 t1 = new T1(t2); //creates a new T1 object and passes a t2 reference to it.
//      T1.start();  //change for naming convention
    t1.start(); //Starts the t1 thread
  }
}
class T1 extends Thread 
 { 
 T1(Runnable runnable) 
 { super(runnable);  //default call to Thread class constructor makes a new thread for runnable, but does not start it.
 } 
 public void run() //method started from main's call t1.start();
 { System.out.println("Hello t1");  //this prints

 } 

 } 

 class T2 implements Runnable 
 { public void run()  //this would be what is started if it were started
 { System.out.println("Hello t2");  //you would get a print here if this were started, but it never is.
 } 
 } 

"Hello t1" will be printed because t2 is never started.

[Campbell Ritchie]

…and welcome to the Ranch

Please always use the code button; you can see how much better the code looks because LM has used it.

[Tushar Goel]

Also the class name.. Its should be meaningful and starts from Capital..

[Mike. J. Thompson]

Just so it's clear to the OP, the reason Les's code prints "Hello t1" and not "Hello t2" is because the T2 Runnable instance is ignored by the T1 thread. The constructor that takes a Runnable instance only has any effect if the run() method is not overridden. If you were to remove the run() method in T1 then that code would print "Hello t2".