Eclipse Collections 12.0 and 13.0 Packed, Released and Ready to Go!
Back to back releases delivered for twice the back to school fun!
Eclipse Collections 11.1 was released in July 2022. Eclipse Collections 12.0 and 13.0 were both released just a a few days apart in June 2025. The 12.0 release had three years worth of work, so the release notes took us longer put together and review.
The releases and release notes are ready to go
Eclipse Collections 12.0 has been in development on Java 11 for a couple of years now. The 12.0 release is a packed with loads of features and improvements.
Read the 12.0 release notes to find out more.
Eclipse Collections 13.0 was released using Java 17. There were no new features added in Eclipse Collections 13.0. The release is compiled using Java 17, which means the end of development for Eclipse Collections with Java 11.
Read the 13.0 release notes to find out more.
Eclipse Collections 14.0 is in development now using Java 17. This means we can finally take advantage of some new language features in the Eclipse Collections project like Records, Text Blocks, and Pattern Matching for instanceof. This also means to leverage Eclipse Collections 13.0 or 14.0 (when it is released), you will need to be on at least Java 17. Progress happens.
Thank you to the contributors
There were a total of 26 contributors who made contributions to Eclipse Collections 12.0. I want to thank all of the contributors for their time, effort, and contributions. It’s through our community of open source contributors that Eclipse Collections continues to evolve and adapt to new requirements and use cases.
Thank you to my co-project lead
Releases are the toughest and least recognized job in an open source project. is the unsung hero of both of these releases. Please join me in thanking Nikhil for all of his amazing hard work getting these releases over the finish line. Thank you!!!
Congratulations to our new committers
Eclipse Collections recently grew from six to eight committers on the project. Congratulations to and for being elected to committer status on the project! Welcome!
https://projects.eclipse.org/projects/technology.collections/who
Thank you to our users!
Eclipse Collections passed one million downloads for the first time in a single month in March 2025 from Maven Central. Thank you to all the projects out there that depend on Eclipse Collections!
Time for another five year wish list
It’s almost been five years since I wrote down everything I wished would eventually be done in Eclipse Collections. There has been some great progress, especially with JUnit 4 -> 5 migration and the evolution of a Java Data Frame library built around Eclipse Collections called dataframe-ec.
We’ve upgraded to Java 11, and then upgraded again to Java 17. I didn’t see that one coming five years ago. We got help from the community simplifying how we deal with Java Modules and OSGi. There have been a bunch of optimizations, and that work continues. I even finally got around to doing some cleanup of our performance tests.
What I hadn’t planned five years ago was writing a book about Eclipse Collections. That happened as well. While I had to use Eclipse Collections 11.1 to write the book, it is the most comprehensive documentation available for the library. The book is currently available to Kindle Unlimited Readers for free until mid-October. So please enjoy reading it there if you already pay for the service! More details about how to obtain the book in the blog below.
There is still a ton of work to do, and we’re always looking for new contributors who want to help make a difference, no matter how big or small. We got asked recently if we would take any more language translations of our website. Absolutely! The only challenge is that someone has to write the translation, and then someone else has to review it. We’ve done this eleven times so far, and this is one of my favorite contributions from the community, because while Eclipse Collections is a global community and we want to be locally accessible.
I’ll write an end of year blog and opine on some of the big and small things we have left to do, in the hopes that folks from the community will see something that inspires and motivates them to make a contribution.
Thanks for reading!
I am the creator of and committer for the Eclipse Collections OSS project, which is managed at the Eclipse Foundation. Eclipse Collections is open for contributions. I am also the author of the book, Eclipse Collections Categorically: Level up your programming game.
