Question

I have a class ThreadClass which looks as follows:

public class ThreadClass extends Thread{

    String msg;

    public void run()
    {
        for(int i=0;i<=5;i++)
        {
            System.out.println("Run method: "+msg);
        }
    }

    ThreadClass(String mg)
    {
        msg=mg;
    }

}

public class MainThreadClass {

    public static void main(String[] args) {

        ThreadClass dt1=new ThreadClass("Thread 1");
        ThreadClass dt2=new ThreadClass("Thread 2");

        dt1.start(); 
        dt2.start(); 

        System.out.println("Finished");
    }
}

the output I am getting is:

Run method: Thread 1
Finished
Run method: Thread 1
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 1
Run method: Thread 1
Run method: Thread 1
Run method: Thread 1

The output I would like to achieve would be:

Run method: Thread 1
Run method: Thread 1
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 2
Run method: Thread 1
Run method: Thread 1
Run method: Thread 1
Run method: Thread 1
Finished

so the string finished is printed out when these two threads terminate. How to do it?

Answer 1

Wait for each thread to exit using join():

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

    ThreadClass dt1=new ThreadClass("Thread 1");
    ThreadClass dt2=new ThreadClass("Thread 2");

    dt1.start(); 
    dt2.start(); 

    dt1.join();
    dt2.join();

    System.out.println("Finished");
  }
}

[Sorry about the lousy formatting, for some reason I can’t get this looking any nicer. IE issue maybe?]