Equals and Hashcode

[Arjun Reddy]

Hi all,

If equals method is overridden, we must override the hashcode method right? is it true the other way round too?

Thanks.

[vidhya suvarna]

If you override either equals() or hashcode(), then you have to override the other one too.

[Arjun Reddy]

Thanks for the reply Vidhya.

[Manju Kavi]

No its not mandatory to override if you do override one.

[ramesh maredu]

No its not mandatory to override if you do override one.

well, if we don't override we will not get any compile time error or run time exception, but it won't work as desired.

[chander shivdasani]

There is a contract between Equals and Hashcode method.

If 2 objects are equal according to Equals method, then their Hashcodes should be same.

As long as this contract is fulfilled, the program will work as required.

[vipin jain]

hello Arjun,

really concept is

if equal() true -then Hashcode () must true => must overriding
if equal() false -then Hashcode() not dependen=> not necessary
if Hashcode() false- Then equal() must false=> must overriding
if Hashcode() true-> Then only request to equal() true=> might be overriding .

it base of my besat knowledege.
if any one no more about this, welcome to him/her.