Brownies Collections complements the Java Collections Framework. GapList combines the strengths of both ArrayList and LinkedList. BigList is a list optimized for storing large number of elements. There are specialized List implementations for all primitive data types. The key collection classes offer support for keys and constraints for lists and collections.
High performance bit set implementations.
A supplement to the Java Collections library.
Dynamic Collections provides a suite of tools to extend and enhance the Java Collections API.
Ponzu is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings.
Efficient Java collections for primitive integer types
Collections library of the Staccatissimo project, focused on providing new abstractions that mix object oriented and functional programming style for dealing with iterable objects.
Trove of primitive collections with Apache 2.0 license, built for Java Java 8
Collections and utilities based on primitives types