How to pass parameter to an already running thread in java?

Question

How to pass parameter to an already running thread in java -- not in the constructor, & probably without using wait() (possible ??)

Something similar to a comme

Answer 1

public class T1 implements Runnable {
    //parameter of thread T1
    public static AtomicBoolean flag = new AtomicBoolean();

    @Override
    public void run() { 
    }   
}

public class T2 implements Runnable {

    @Override
    public void run() { 
        //parameter to an already running thread
        T1.flag.set(true);
    }   
}