I made a new class CustomMap that implements Map. It's basically a new Map class that has more features for example getting a key using the value and removing a key using the value. CustomMap: http://hastebin.com/sijojudafo.java It's quite easy to make things that implement already made java classes such as Map and List once you get used to using the 'K' and 'V' value. You'll understand when you read through my code.