Question

I know that I can use the following to have thread B waiting for thread A to finish before proceeding:

class A extends Thread{
    public void run(){
        ....
    }
}
class B extends Thread{
    private Thread someThread;
    B(Thread t){
        someThread=t;
    }
    public void run(){
        someThread.join();
        ...//then proceed
    }
}

But how can I do this in the run() of A to call B and then wait it finish before proceeding? That is, I want something like

class A extends Thread{
    private Thread someThread;
    B(Thread t){
        someThread=t;
    }
    public void run(){
        //*how to start B and wait it finish?
        ...//then proceed
    }
}
class B extends Thread{
    public void run(){
        ....
    }
}

Answer 1

If possible, a simpler solution would be to start B first, then b.join();, and do the same for A in the client code:

b.start();
b.join();
a.start();
a.join();

There is no sense in starting a thread for it to just fire up and join on another tread before proceeding.