java多线程时钟，在eclipse运行效果不好

import java.util.Calendar;


public class Clock {


    public static void main(String[] args) {

        Thread clockThread = new Thread(new Runnable() {

            @Override

            public void run() {

                while (true) {

                    try {

                        Calendar now = Calendar.getInstance();

                        int hour = now.get(Calendar.HOUR_OF_DAY);

                        int minute = now.get(Calendar.MINUTE);

                        int second = now.get(Calendar.SECOND);

                        System.out.printf("\r%02d:%02d:%02d", hour, minute, second);
	         

                        Thread.sleep(1000);

                    } catch (InterruptedException e) {

                        e.printStackTrace();

                    }

                }

            }

        });

        clockThread.start();

    }

}