Comparison of programming languages (associative array): Difference between revisions

Revision as of 07:30, 30 January 2012

Revision as of 00:48, 4 February 2012

Line 429:

For two objects ''a'' and ''b'',

* <source lang="java">
a.equals(b) == b.equals(a)</source>

* <source lang="java">if a.equals(b), then a.hashCode() == b.hashCode()
</source>

In order to maintain this contract, a class that overrides <code>equals()</code> must also override <code>hashCode()</code>, and maybe vice versa, so that <code>hashCode()</code> is based on the same properties (or a subset of the properties) as <code>equals()</code>.