Set

1. /**
2. *@(#)SetExample.java
3. *
4. *
5. *@author
6. *@version1.002008/9/28
7. */
9. importjava.util.*;
10. publicclassSetExample{
13. publicSetExample(){
15. }
16. publicstaticvoidmain(String[]args)
17. {
18. Set<Integer>s1=newHashSet<Integer>();
19. Collection<Integer>s2=newHashSet<Integer>();
20. inti;
21. for(i=0;i<10;i++)
22. s1.add(i);
23. for(i=10;i<100;i++)
24. s2.add(i);
26. for(i=10;i<20;i++)
27. s2.add(i);
28. System.out.println("beforeretainAlls1:"+s1);
29. System.out.println("beforeretainAlls2:"+s2);
30. s2.retainAll(s1);
31. System.out.println("afterretainAlls2:"+s2);
32. s2.addAll(s1);
33. System.out.println("afetraddAlls2"+s2);
34. s2.clear();
35. System.out.println("afterclear:s2"+s2);
39. }
42. }
43. //result:
44. before retainAll s1:[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    before retainAll s2:[10, 11, 12, 13, 14, 15, 17, 16, 19, 18, 21, 20, 23, 22, 25, 24, 27, 26, 29, 28, 31, 30, 34, 35, 32, 33, 38, 39, 36, 37, 42, 43, 40, 41, 46, 47, 44, 45, 51, 50, 49, 48, 55, 54, 53, 52, 59, 58, 57, 56, 63, 62, 61, 60, 68, 69, 70, 71, 64, 65, 66, 67, 76, 77, 78, 79, 72, 73, 74, 75, 85, 84, 87, 86, 81, 80, 83, 82, 93, 92, 95, 94, 89, 88, 91, 90, 98, 99, 96, 97]
    after retainAll s2:[]
    afetr addAll s2[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    after clear:s2[]