Apache Commons Collections

Clone this repo:
  1. 2e2cd9c Bump codecov/codecov-action from 4.4.0 to 4.4.1 (#496) by dependabot[bot] · 3 days ago master
  2. 5d93e5e Javadoc by Gary Gregory · 5 days ago
  3. 88b8eb2 Add comment by Gary Gregory · 6 days ago
  4. c1d10c4 Add Java 22 and 23-ea to GH CI by Gary Gregory · 6 days ago
  5. 3218cb7 Add Java 22 and 23-ea to GH CI by Gary Gregory · 6 days ago

Apache Commons Collections

Java CI Coverage Status Maven Central Javadocs CodeQL OpenSSF Scorecard

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


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.

Getting the latest release

You can download source and binaries from our download page.

Alternatively, you can pull it from the central Maven repositories:



Building requires a Java JDK and Apache Maven. The required Java version is found in the pom.xml as the maven.compiler.source property.

From a command shell, run mvn without arguments to invoke the default Maven goal to run all tests and checks.


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 existing code style for each file.
  • 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.

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.


This code is licensed under the Apache License v2.

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


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

Additional Resources

Apache Commons Components

Please see the list of components