Threads

[Deepali Pate]

public class Question10 {
public static void main(String[] args) {
new Question10().doSomething();
}
public void doSomething(){
final int i=5;
Thread t = new Thread(new Runnable(){
public void run(){
for(int j=0;j<=i;j++){
System.out.print(" "+j);
}
}
});
t.start();
}
}

This is a program from Vals exam can someone explain path of execution of this program.
Thanks
[Edited by Val - Added code tags]
[ July 02, 2002: Message edited by: Valentin Crettaz ]

[manasa teja]

The above code canbe interpreted as follows..
HTH
murthy

 public class Question11 implements Runnable {
final int i=5;
public void run() {
for(int j=0;j<=i;j++){
System.out.print(" "+j);
 } } //run close
public static void main(String[] args) {
new Question11().doSomething();
}
public void doSomething(){
Thread t = new Thread(new Question11());
t.start();
}
} 

[ July 02, 2002: Message edited by: Murthy Ram ]

[Valentin Crettaz]

Good intention Murthy, but your code created two objects Question11 which is not really elegant.
I would rewrite your code like this:

public class Question11 implements Runnable {
   final int i=5;
   public void run() {
      for(int j=0;j<=i;j++){
         System.out.print(" "+j);
      } 
   } //run close
   public static void main(String[] args) {
      new Question11().doSomething();
   }
   public void doSomething(){
      Thread t = new Thread(this);
      t.start();
   }
}

Note that when we create the thread t, we provide a reference to this Question11 object.

[Deepali Pate]

But in my original code where is the implements Runnable happening???

[Deepali Pate]

If the implements is not mentined then can we still create and object of Runnable??

[Amir Ghahrai]

Runnable is an interface and can't be instancitated. however, the in-line implementation of the runnable interface can be done as shown in the original code, as an annonymous inner class and doesn't require the implements clause.

[zarina mohammad]

In the your original code..
you are creating the anonymous inner class(Runnable implicitly implementing Runnable interface) in the thread constructor. providing the implementation for run and then scheduling the thread using start().

[Deepali Pate]

Thread t = new Thread(new Runnable(){public void run(){for(int j=0;j<=i;j++){System.out.print(" "+j);}}});
This one statement is a way of creating an annonymous object of Runnable interface ???
Is my understanding right?
I still wonder how Runnable gets implicitly implemented is that true with any interface.
Thnx for ur replies
B

[Amir Ghahrai]

Thread t = new Thread(new Runnable(){ public void run(){ for(int j=0;j<=i;j++){ System.out.print(" "+j); } } });
This one statement is a way of creating an annonymous object of Runnable interface ???

That's correct. although the syntaxt may be a little bit strange, you are actually implementing the Runnable interface. You can implement any interface like that as an anonymous inner class, the same you do with event listener interfaces.