Custom hashing strategy for primitive maps with object as key would be a very nice new feature!

[javafanboy]

I would love to be able to use even final classes I have no control over that by default uses "object" equals and hashCode as keys in for instance an ObjectInteger map by providing my own alternative hashing strategy (equals & hashCode).
This is interesting in particular in situations where we want to write algorithms that at steady state is as allocation free as possible.