Collection override for equals

Question

Hi,
i have a Collection X of objects and i would like to use X.contains(blah) to check for an obect's existence. The problem is that 5 out of the six fields in the object are the same but the sixth is different.
Object o1 {
x=10;
a=1;
b=1;
c=1;
d=1;
e=1;
Object o2 {
x=20;
a=1;
b=1;
c=1;
d=1;
e=1;
These would be equal .. because the first field is irrelevant!
So, the Collection X reads {o6, o7, o8, o2} and X.contains(o1) returns true. OK? So how do i get this scenario?
Thanks.

Answer 1

I have a Set and I add objects of a class that has the method equals defined. Howerver the object equals method is not called when I do a contains(object). What is it that I am doing wrong?
public class TSet {
public TSet() {
Set s = new HashSet();
s.add(new MyTest("A","B"));
MyTest t = new MyTest("A","B");
// I was expecting that the equals in MyTest object
// would be called but it is not
if(s.contains(t))
System.out.println("found:" + t);
else
System.out.println("not found:" + t);
MyTest x = new MyTest("X","B");
if(s.contains(x))
System.out.println("found:" + x);
else
System.out.println("not found:" + x);
* @param args the command line arguments
public static void main(String[] args) {
new TSet();
class MyTest{
String a = null;
String b = null;
private MyTest(){}
public MyTest(String a, String b)
this.a = a;
this.b = b;
public boolean equals(Object o)
return equals((MyTest)o);
public boolean equals(MyTest t)
if(a.equals(t.a) && b.equals(t.b))
return true;
else
return false;
public String toString()
return " a=[" + a + "] b=[" + b + "]";