Commons Collections

Collections aims to provide:

The Javadoc of the latest version is available.


Releases & Compatability

The latest release (v3.2) can be downloaded here.

Two releases of Collections are currently in common use - v2.x and v3.x. These releases are source compatible (with deprecations). Unfortunately, due to human error, these releases are binary incompatible in the IteratorUtils class. If you don't use this class, then the two versions are binary compatible.

All users of v2.1 should upgrade to v2.1.1, and all users of v3.0 should upgrade to v3.1 to help solve the issue.

Unofficial Releases

John Watkinson and Matt Hall have a release of a fully type safe Collections ported to Java 1.5 generics. It can be downloaded from for now and commented on in the development mailing lists.

Upcoming Releases


You can give feedback on what you would like included in future releases by contacting the mailing list, prefixing you email by [collections]. Alternatively add a comment here:


This article explains real world usage of Commons Collections and samples are provided for a few.

Collections (last edited 2009-09-20 23:48:45 by localhost)