mastodon 4.8.0-nightly.2026-10-06Author. Java Champion. Writer of blogs. Creator of the OSS Java library Eclipse Collections. Inspired by Smalltalk. Opinions are my own.
Author of "Eclipse Collections Categorically: Level up your programming game"
Do you love a good mystery? Do you know what the type "java.util.Collections$2" is in #Java? I didn't know until I blogged about it.👇
In my latest blog, I explain this and other mysterious class names you may encounter in Java.
Thanks for reading! 🙏
https://donraab.medium.com/what-if-java-consistently-used-intention-revealing-names-for-types-7b9cbc39f65f?source=friends_link&sk=38d28dba7f021f2bcf7f41378e6600e8
I've been writing about better building blocks in #Java. Several blogs since March 2026 including:
• Empty should be empty
• Lazy & eager performance
• Memory costs for lazy iteration
• Intention Revealing Names
• Collecting Collectors
• "Fat-free" Lambdas
• Snow Leopards & Tribbles
Stories to inspire, including the blog linked below from March 2025. 🙏
https://donraab.medium.com/building-better-building-blocks-7e61dc71d519?source=friends_link&sk=a2c8fab54004249e705f190e83422b2f
I still won't use GenAI for art or writing. Why? This was my idea. I clicked and dragged the shapes with the mouse. I fiddled with the fills. I drew the legs on the cuboid. This is my opus. The computer was my canvas, not just a prompt for someone else's muse. 🎨🧑🎨
https://donraab.medium.com/computer-aided-in-the-eighties-4439316e1fc0?source=friends_link&sk=225541aa6fe4cf94697a2e7d8f881709
Seen on a heap.
String: 3.4 million instances
byte[]: 3.7 million instances
Stream: Hold my 🍺
MatchOps: Hold my 🍺🍺🍺
Shocked I was able to see so many ReferencePipeline$Head (Stream) and MatchOps inner class instances in a jmap heap histogram. Created and gone in a few blinks of an eye.
Cheers to the amazing developers who make object allocation blazingly fast and to the developers who build the world class Java garbage collectors. Thank you! 🍺🍺🍺
For folks who haven't looked at #EclipseCollections because they don't use the Eclipse IDE. Eclipse Collections (EC) and the Eclipse IDE are both independent projects at the Eclipse Foundation. 💡
Note: I created EC and have coded with IntelliJ for 24 years. 🙏
https://donraab.medium.com/explaining-the-eclipse-prefix-in-eclipse-collections-1d9850d20047?source=friends_link&sk=e6ee8d28bda7a66e2125083de49e8fa4
This was a very nice surprise, announced during the first JavaOne that I have missed in over a decade. Thank you to the JCP and Heather VanCura. Thanks to Chandra Guntur for attending the JCP Event at JavaOne 2026, accepting and then hand delivering the award. 🙏
https://donraab.medium.com/on-winning-jcp-member-participant-of-the-year-for-2025-at-javaone-2026-3c977f7049da?source=friends_link&sk=ab73b42c391a3a734db6a9b1d6ee21e8
"Saving the planet, one Collector at a time."
I can't un-new the billions of Collector instances that were created since 2014, but I can share ideas and alternatives for the future. Thanks for reading! 🙏
#Java #EclipseCollections
https://donraab.medium.com/counting-and-collecting-collectors-d69b7c9aaca0?source=friends_link&sk=ef73f56026d1afcf97e869f8ae990ea9
Have you upgraded to #Java 25 and enabled Compact Object Headers yet?
This image at the end of my last GitHub code review was giving me all the apocalyptic feels.
A fun blog about Eclipse Collections.
https://www.fxjavadevblog.fr/eclipse-collections-en/
My latest blog: Snow Leopards and Tribbles in Java Heaps
https://donraab.medium.com/snow-leopards-and-tribbles-in-java-heaps-a3f20fd5520c?source=friends_link&sk=f82a9c0eed80bcc1330ce94781f48ae7
I can't predict the future. I believe we can all help invent the future when we work together. Our present is a bit murky and uncertain. If it isn't the future we want or need, maybe we shouldn't be chasing it so hard.
https://donraab.medium.com/the-future-ecbc2e3b2054?source=friends_link&sk=df1850466a2999600fd475d673e31d0b
In the early days of the pandemic, I wrote a blog titled "Eager is Easy, Lazy is Labyrinthine." I struggle with spelling Labyrinthine every single time. I could have used mazy instead and rhymed, but I like the challenge of spelling labyrinthine. 🤷♂️
https://medium.com/javarevisited/eager-is-easy-lazy-is-labyrinthine-b12605f13048?source=friends_link&sk=9d8ec91aa6f1af48ee7333ad03b19ed0
Add this to the list of things I hadn't thought to measure with JOL before, but now that I did, I'll be more careful with local capture of variables in lambdas.
https://stackoverflow.com/questions/79932789/how-to-measure-the-memory-cost-of-lambdas-in-java-25