多选题 Given:
2. public class DMV implements Runnable {
3. public static void main(String[] args) {
4. DMV d = new DMV();
5. new Thread(d) .start();
6. Thread t1 = new Thread(d);
7. tl.start();
8. }
9. public void run() {
10. for(int j = 0; j ＜ 4; j++) {do1(); do2(); }
11. }
12. void do1() {
13. try {Thread.sleep(1000); }
14. catch (Exception e) {System.out.print("e "); }
15. }
16. synchronized void do2() {
17. try {Thread.sleep(1000); }
18. catch (Exception e) {System.out.print("e ");
19. } }
Which are tree? (Choose all that apply.)