How a thread can wait on itself?

[Maduranga Liyanage]

Hello,

I'm not sure how this can be done.

This is what I want to do:

public static void main(String[] args) {
 
Thread T = new Thread_extended_class();
T.start();
T.join();
 
int user_input_value = value;
 
}
 

class Thread_extended_class extends Thread implements ActionListener {
  public void run() {
    //present a GUI for the user to input 'value';
    T.wait();
  }
 
  public void actionPerformed(ActionEvent ev) {
   //read the value.
   T.notify();
  }
}

What I want to do is for the main to read the user input value 'after' the user has actully input it. But when I do T.start(), it starts the thread and then immediately reads the value before user inputs it.

I want some way to wait till the user inputs it. So I did join() in main method, and I wait() in run() method and finally when the user is finished input it notify() so the main method will the value 'after' the user has input it.

But this doesn;t seem to work.
I even tried 'this' instead of 'T' but with no luck.

Thank you.