The Google Collections Library 1.0 is a set of new collection types, implementations and related goodness for Java 5 and higher, brought to you by Google. It is a natural extension of the Java Collections Framework you already know and love.

We are now posting release candidates for the final 1.0 release. Until the release is final, the API is still subject to change. (However, these changes should be very minimal at this point.)

Download 1.0 Release Candidate 2 nowThe library consists of:

New Collection types: Multimap, Multiset, BiMap and others High-performance immutable implementations of the standard collection types, for example ImmutableSet MapMaker, a builder for concurrent hash maps with many advanced features Ordering, which can only be described as a "Comparator on stero