The next 5 years for Eclipse Collections

3 min readDec 31, 2020

My top 25 wish list for the future of Eclipse Collections development

9 Years OSS, 5 years at Eclipse Foundation

Eclipse Collections has existed as an open source project on GitHub for a total of 9 years. Eclipse Collections has been a project at the Eclipse Foundation for 5 years. There have been 4 major versions of Eclipse Collections released, and there were 7 major versions of GS Collections prior to that.

The open source community has done a lot of work on this amazing library, and I would like to thank everyone who has contributed and continues to contribute their time, spirit and code. There is plenty more that can be done to evolve the library, and it will continue to be work done by the community for the community. This makes it kind of hard to predict anything, but I can easily make a wish list.

More of this, Less of that

It’s always nice to consider what new features should be added to a library, but in order to move forward we also have to pay down the technical debt.

Here’s my wish list for Eclipse Collections for the next 5 years.

Technical Debt

Combine Unit Tests and Unit Tests Java 8 modules
Replace Scala Unit Tests with Java Equivalent Tests
Remove JMH Scala Tests
Refresh and update the Eclipse Collections Reference Guide
Improve JavaDoc
Move slow running unit tests to acceptance tests
Replace legacy anonymous inner classes with lambdas and method references
Clean up performance tests

Java Upgrades

Upgrade library to Java 11
Leverage Java Module System fully
Leverage Local Variable Type Inference sparingly to improve readability
Test and integrate with Project Valhalla features
Upgrade to JUnit 5

New Containers

DataFrames
Trees
More primitive collection types
Lazy Collections (specific types like LazyList)
Off-heap Collections
Persistent Collections (Functional)

New APIs

Improve symmetry between object and primitive APIs
More converter methods between types
Implement more Parallel APIs

Performance Tuning

Optimize APIs from JDK

IDE Refactoring Support

Refactor from Java Streams to Eclipse Collections
Refactor from for-loops to Eclipse Collections
Refactor from Object collections to Primitive Collections

Growing the community

I would love to see more projects using and benefitting from the engineering investment we have collectively made in Eclipse Collections. Here’s my top 10 Project list that I would like to see include the goodness of Eclipse Collections.

The future is up to you, the contributor

Is there something missing from my wish list that you would like to see in Eclipse Collections? You have the power to impact and influence with your voice and your keyboard. Eclipse Collections is open for contributions, and we’d love to have more contributors helping shape the future of the library.

Have a Happy, Safe and Healthy New Year!

I am a Project Lead and Committer for the Eclipse Collections OSS project at the Eclipse Foundation. Eclipse Collections is open for contributions. If you like the library, you can let us know by starring it on GitHub.