Google Guava
Google Guava is an open-source set of common libraries for Java, mainly developed by Google engineers. == Overview == Google Guava can be roughly divided into three components: basic utilities to reduce manual labor to implement common methods and behaviors, an extension to the Java collections framework (JCF) formerly called the Google Collections Library, and other utilities which provide convenient and productive features such as functional programming, graphs, caching, range objects, and hashing.