????????????????????

public class LiftOff implements Runnable{
protected int countDown = 10;
private static int taskCount = 0;
private final int id = taskCount++;
public LiftOff() {}
public LiftOff(int countDown) {
this.countDown = countDown;
}
public String status() {
return "#" + id + "(" + (countDown > 0 ? countDown : "LiftOff!") + ")";
}
/* (non-Javadoc)
* @see java.lang.Runnable#run()
*/
@Override
public void run() {
while (countDown-- > 0) {
System.out.println(status());
Thread.yield(); // ????CPU???????????л???
}
}
}
????????????????????′????????????????????????????t.start()??????????? LiftOff???run??????
Thread t = new Thread(new LiftOff());
t.start();