Guava
Google Core Libraries for Java — collections, caching, primitives, and more.
Language: JavaCategory: UtilityFirst released: 2009Created by: Google (Kevin Bourrillion)License: Apache-2.0
Guava is an open-source set of common libraries for Java, primarily developed by Google engineers. It fills gaps in the Java standard library with utilities for collections, caching, primitives support, concurrency, common annotations, string processing, I/O, and validation. Guava is one of the most widely used Java libraries and serves as a proving ground for APIs that sometimes later become part of the JDK itself.
Links
Key Features
Enhanced collection types (Multiset, Multimap, BiMap, Table)Immutable collection factoriesCache builder with eviction policies (size, time, reference)Preconditions for defensive programmingFunctional-style utilities (transform, filter)Event bus for publish-subscribe messagingGraph library for network and graph structuresHashing, Bloom filters, and math utilities