public class TT implements Runnable {
    private int b = 100;

    public void m1() {
        synchronized (this) {
            try {
                Thread.sleep(3000);
                b = 1000;
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("b1 = " + b);
        }
    }

    public void m2() {
        System.out.println("b2 = " + b);
    }

    public void run() {
        this.m1();
    }

    public static void main  (String[] args) throws Exception {
        TT t = new TT();
        Thread t1 = new Thread(t);
        t1.start();
        Thread.sleep(500);
        t.m2();
    }
}