HashMap vs EnumMap in Java
What is difference between EnumMap and HashMap in Java is the latest Java collection interview question which has been asked to couple of my friends. This is one of the tricky Java question, specially if you are not very much familiar with EnumMap in Java, which is not uncommon, given you can use it with only Enum keys. Main difference between EnumMap and HashMap is that EnumMap is a specialized Map implementation exclusively for Enum as key. Using Enum as key, allows to do some implementation level optimization for high performance which is generally not possible with other object's as key. We have seen lot of interview questions on HashMap in our article How HashMap works in Java but what we missed there is this question which is recently asked to some of my friend. Unlike HashMap, EnumMap is not applicable for every case but its best suited when you have Enum as key. We have already covered basics of EnumMap and some EnumMap example in my last article What is EnumMap in Java and In this post we will focus on key differences between HashMap and EnumMap in Java.