Eclipse Collections is a collections framework for Java with optimized data structures and a rich, functional and fluent API.

fastutil extends the Java™ Collections Framework by providing type-specific maps, sets, lists and queues.

A Primitive Collection library that reduces memory usage and improves performance

Java library providing primitive collections.

Library built under the fastutil which offers various methods for creating collections, which makes your code more efficient and faster

Java primitive collections for char, int, float, long, and double Lists, SortedLists, ArrayViews, Iterators, and Maps.