多选题 Given:
1. class Locker extends Thread {
2. private static Thread t;
3. public void run() {
4. if (Thread.currentThread() == t) {
5. System.out.print ("1 ");
6. synchronized(t) {doSleep(2000); }
7. System.out.print("2 ");
8. } else {
9. System.out.print ("3 ");
10. synchronized(t) {doSleep(1000); }
11. System.out.print("4 ");
12. }
13. }
14. private void doSleep(long delay) {
15. try {Thread.sleep (delay); } catch(InterruptedException ie) { ; }
16. }
17. public static void main (String args[]) {
18. t = new Locker();
19. t.start();
20. new Locker() .start();
21. } }
Assuming that sleep() sleeps for about the amount of time specified in its argument, and that all other code runs almost instantly, which are true? (Choose all that apply.)