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what are the senarios when we should override equals and hashcode

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  what are the senarios when we should override equals and hashcode Ajay Paul <ajaykpaul@gmail.com> - 2015-05-02 17:39 -0700
    Re: what are the senarios when we should override equals and hashcode Arne Vajhøj <arne@vajhoej.dk> - 2015-05-03 10:50 -0400
    Re: what are the senarios when we should override equals and hashcode Lew <lewbloch@gmail.com> - 2015-05-12 14:17 -0700

#31641 — what are the senarios when we should override equals and hashcode

What are the senarios when we should override equals and when we don't have to the same.

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#31644

On 5/2/2015 8:39 PM, Ajay Paul wrote:
> What are the senarios when we should override equals and when we don't have to the same.

You should override them when you need to them to overridden.

:-)

A typical case would be data classes where you need to compare
instances either explicit in your code or implicit by stuffing
them into collections and let the collection code do the comparisons.

Arne

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#31686

On Saturday, May 2, 2015 at 5:40:01 PM UTC-7, Ajay Paul wrote:
> What are the senarios when we should override equals and when we don't have to the same.

If you compare objects by identity, i.e., "Equality means it is the exact same object", then you don't override 'equals()', 'hashCode()' (not "hashcode()"), 'toString()', or 'compareTo()'. If you compare objects by state, then you must override 'equals()' and 'hashCode()', you should override 'toString()', and if you implement 'Comparable', 'compareTo()'. All four methods (where all four exist) should be consistent with each other.

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