collections

Types that extend and augment the Java Collections Framework.

The Apache Commons Collections package contains types that extend and augment the Java Collections Framework.

This library makes some new Scala APIs (mainly collections) available to older versions of Scala.

fastutil extends the Java Collections Framework by providing type-specific maps, sets, lists, and queues with a small memory footprint and fast access and insertion; it provides also big (64-bit) arrays, sets and lists, sorting algorithms, fast, practical I/O classes for binary and text files, and facilities for memory mapping large files. Note that if you have both this jar and fastutil-core.jar in your dependencies, fastutil-core.jar should be excluded.

The Trove library provides high speed regular and primitive collections for Java.

Eclipse Collections Main Library

Google Collections Library is a suite of new collections and collection-related goodness for Java 5.0

Eclipse Collections API

Standalone efficient collections.

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap memory. It is a fast, scalable and easy to use embedded Java database.