Apache Commons Collections

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

Documentation

More information can be found on the Apache Commons Collections homepage. The JavaDoc can be browsed. Questions related to the usage of Apache Commons Collections should be posted to the user mailing list.

Where can I get the latest release?

You can download source and binaries from our download page.

Alternatively you can pull it from the central Maven repositories:

<dependency>
  <groupId>org.apache.commons</groupId>
  <artifactId>commons-collections4</artifactId>
  <version>4.1</version>
</dependency>

Contributing

We accept Pull Requests via GitHub. The developer mailing list is the main channel of communication for contributors. There are some guidelines which will make applying PRs easier for us:

• No tabs! Please use spaces for indentation.
• Respect the code style.
• Create minimal diffs - disable on save actions like reformat source code or organize imports. If you feel the source code should be reformatted create a separate PR for this change.
• Provide JUnit tests for your changes and make sure your changes don't break any existing tests by running mvn clean test.

If you plan to contribute on a regular basis, please consider filing a contributor license agreement. You can learn more about contributing via GitHub in our contribution guidelines.

License

This code is under the Apache Licence v2.

See the NOTICE.txt file for required notices and attributions.

Donations

You like Apache Commons Collections? Then donate back to the ASF to support the development.

Additional Resources

• Apache Commons Homepage
• Apache Bugtracker (JIRA)
• Apache Commons Twitter Account
• #apache-commons IRC channel on irc.freenode.org