Friday, 8 July 2016

Comparing Java enum members: == or equals()?



I know that Java enums are compiled to classes with private constructors and a bunch of public static members. When comparing two members of a given enum, I've always used .equals(), e.g.



public useEnums(SomeEnum a)
{
if(a.equals(SomeEnum.SOME_ENUM_VALUE))
{

...
}
...
}


However, I just came across some code that uses the equals operator == instead of .equals():



public useEnums2(SomeEnum a)
{

if(a == SomeEnum.SOME_ENUM_VALUE)
{
...
}
...
}


Which operator is the one I should be using?


Answer




Both are technically correct. If you look at the source code for .equals(), it simply defers to ==.



I use ==, however, as that will be null safe.


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