Hashcode and Equals

[harmeet saini]

Hi
I am very much confused regarding this " if equals is overridden should hashCode also be overridden"

I am confused coz in CertPal i found two explanations

1) Nothing can prevent a progremmer for not overriding hashCode when overiding equals

2) if equals is overridden should hashCode also be overridden

[Seetharaman Venkatasamy]

http://www.javaworld.com/community/?q=node/1006

[Abimaran Kugathasan]

harmeet saini wrote:Hi
I am very much confused regarding this " if equals is overridden should hashCode also be overridden"

I am confused coz in CertPal i found two explanations

1) Nothing can prevent a progremmer for not overriding hashCode when overiding equals

2) if equals is overridden should hashCode also be overridden

This is a conract, not a must. It doesn't create any syntatic problem wen compiling, but you'll get some logical problems, if you don't override for your own purposes. Check the equal/hashCode contracts.

[Deepak Bala]

Nothing can prevent a progremmer for not overriding hashCode when overiding equals

This is a contract, not a must.

Yep. You will not get compile time errors, but you will encounter problems when you put your custom classes into collections that rely on hashing