Thread - join method

[Cliff DeRose]

I have a SCJD exam review book, which tries to explain the join method you can call on a Thread instance. However, its a little confusing to me. Could someone please explain exactly how the join method works when you call it on a Thread instance.
Thanks,
Cliff

[Ray Stojonic]

The Thread.join method will not return to the caller until: 1) the thread join was called on dies, or 2) the specified amount of time elapses.
try the following code, both as is and with the try:join block commented out to see this in action

public class ThreadJoin {
  public static void main( String[] args ) {
    T t = new T();
    t.start();
    try {
      t.join();
    } catch( InterruptedException ie ) {
      System.out.println( "ahem, as I was saying: " + ie );
    }
    System.out.println("End main");
  }
}
class T extends Thread {
  public void run() {
    for( int i = 0; i < 3; ++i ) {
      try {
        sleep(1000);
        System.out.println("In run");
      } catch( InterruptedException ignored ) {}
    }
  }
}

[ January 12, 2004: Message edited by: Ray Stojonic ]

[Cliff DeRose]

Thanks so much. It is much easier to understand after seeing it in action.