Using two (or more) objects as a HashMap key

Question

I want to store certain objects in a HashMap. The problem is, usually you just use a single object as a key. (You can, for example, use a String.) What I want to do it to us

Answer 1

Apache Commons Collections has a multikey map which might do the trick for you:

https://commons.apache.org/proper/commons-collections/apidocs/org/apache/commons/collections4/keyvalue/MultiKey.html

It looks like it will handle up to 5 "keys".

Answer 2

I tend to use a list

map.put(Arrays.asList(keyClass, keyString), value)