Over ride the equal method in java

Hi ,
I have doubt about on over ride the equal ? What is the main purpose of over ride the equal method ?
If equal method is override then why hash code method can be over ride?
sorry , If i am not post the right place .

You have to override the equals method when your class has a notion of logical equality, because in that case you need more that the default one (the default one return true only if the reference of the compared Object is the same).
A good exemple is Date, where we consider that is two Dates have the same getTime() they are equals.
You can found more information in this article:
http://java.sun.com/developer/Books/effectivejava/Chapter3.pdf
Edited by: yannig on 16 déc. 2010 03:42: Joachim beat me...
Edited by: yannig on 16 déc. 2010 03:45

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import java.util.*;
class Nearly{
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public boolean equals(Object n)
{I guess my question is about the overriding the equals() method which i am not able to understand

pksingh79 wrote:
what would be the result if we overrode the equals method properlyThe result would be a method, the functionality of which would adhere to Object#equals()'s contract:
public boolean equals(Object obj)
Indicates whether some other object is "equal to" this one.
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* It is reflexive: for any non-null reference value x, x.equals(x) should return true.
* It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and
only if y.equals(x) returns true.
* It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and
y.equals(z) returns true, then x.equals(z) should return true.
* It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y)
consistently return true or consistently return false, provided no information used in equals
comparisons on the objects is modified.
* For any non-null reference value x, x.equals(null) should return false.

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Over ride the equal method in java

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