1 Set s1=new HashSet();
2 Set s2=new HashSet();
3 s1.add("a");
4 s1.add("b");
5 s1.add("c");
6 s2.add("d");
7 s2.add("a");
8 s2.add("b");
9 Set sn=new HashSet(s1);
10 sn.retainAll(s2);
11 Set su=new HashSet(s1);
12 su.addAll(s2);
13 System.out.println(sn);
14 System.out.println(su);
1 import java.util.*;
2
3 class Name
4 {
5 private String firstName,lastName;
6
7 public String getFirstName() {
8 return firstName;
9 }
10
11 public void setFirstName(String firstName) {
12 this.firstName = firstName;
13 }
14
15 public String getLastName() {
16 return lastName;
17 }
18
19 public void setLastName(String lastName) {
20 this.lastName = lastName;
21 }
22 public Name(String firstName,String lastName)
23 {
24 this.firstName=firstName;
25 this.lastName=lastName;
26 }
27 public boolean equals(Object obj)
28 {
29 if (obj instanceof Name)
30 {
31 Name name=(Name)obj;
32 return (firstName.equals(name.firstName)) && (lastName.equals(name.lastName));
33 }
34
35 return super.equals(obj);
36 }
37 public int hashCode()
38 {
39 return firstName.hashCode();
40 }
41 public String toString() { return firstName + " " + lastName; }
42
43 }
44
45
46
47 public class testmy1 {
48
49 public static void main(String[] args)
50 {
51 Set s=new HashSet();
52 s.add("hello");
53 s.add("world");
54 s.add(new Name("f1","f2"));
55 s.add(new Integer(100));
56 s.add(new Name("f1","f2"));
57 s.add("hello");
58 System.out.println(s);
59 }
60
61 }
