Question

I would like to close all threads that are running (if there are) when my main method is called.

public static void main(String[] args) throws Exception {
  // Close all thread except current one
  ...
  // Remaining of my program
}

Answer 1

This is how I fixed my problem.
First, I interrupt the thread that can be itself interrupted :

Thread.currentThread().interrupt();

In main class (or thread), I detect that my previous thread is not alive anymore and then close the last living thread :

Thread trx = new Thread(clTh);
Thread ttx = new Thread(csTh);

trx.start();
ttx.start();
while(trx.isAlive()) {
    Thread.currentThread().sleep(1000);
}

while(ttx.isAlive()) {
    ttx.interrupt();
    Thread.currentThread().sleep(1000);
}

Then in my second thread, that was waiting for a in.readLine(), I handle it that way, testing in.ready().