Difference between Fast Map and traditional Map

I want to know what is the difference between a standard implementation of java.util.Map interface and some other map implementations which are called Fast Map. And, can you please introduce me some fast map implementations to use?

开发者_如何学GoBest

A general map implementation is something like HashMap. A Fast Map is designed to optimize for reading, but is usually much more expensive to modify. I found this with a quick google search I've never tried it, but it looks pretty good. Link Also, here is the Apache collections page, which has stuff like FastLists and other cool collections.