Charles Oliver Nutter
@headius.bsky.social
JRuby co-lead, Java champion, Ruby hero, JavaOne Rockstar, international traveler and speaker. Book me for your next event! I depend on your donations and sponsorships! https://github.com/sponsors/headius
JRuby 10.1 is just a few dozen tests away from being Ruby 4.0 compatible. We should be able to release in the next few weeks. Feels good to stay caught up and get our recent performance work out to users along with up-to-date compatibility!
January 13, 2026 at 11:24 PM
JRuby 10.1 is just a few dozen tests away from being Ruby 4.0 compatible. We should be able to release in the next few weeks. Feels good to stay caught up and get our recent performance work out to users along with up-to-date compatibility!
Anyone who claims LLMs are going to replace all developers is ignoring the fact that they can only generate code based on existing examples that depend on APIs, runtimes, and kernels that are original and unique. Is your LLM writing apps in assembly? Yeah, didn't think so.
January 10, 2026 at 9:13 PM
Anyone who claims LLMs are going to replace all developers is ignoring the fact that they can only generate code based on existing examples that depend on APIs, runtimes, and kernels that are original and unique. Is your LLM writing apps in assembly? Yeah, didn't think so.
The 2026 season of First Robotics Challenge looks like a banger! Lots of chaos with ball-shooting, scoring phases, and a single climbing tower. Headius Enterprises will sponsor our local team...more details on that soon! www.firstinspires.org/resources/li...
Season Materials | FIRST Robotics Competition
Access official FIRST Robotics Competition game materials, robot build kits, and resources to help your team design, build, and compete with confidence.
www.firstinspires.org
January 10, 2026 at 5:30 PM
The 2026 season of First Robotics Challenge looks like a banger! Lots of chaos with ball-shooting, scoring phases, and a single climbing tower. Headius Enterprises will sponsor our local team...more details on that soon! www.firstinspires.org/resources/li...
Today I'm I enjoying my Golden Yunnan tea from Rishi, similar to English Breakfast tea but earthier and more flavorful.
I also got samples of their Pu'er and Wild Thai teas. The tea quality from Rishi is hard to beat and emboldens me to try new things.
buff.ly/TkEbz4s
I also got samples of their Pu'er and Wild Thai teas. The tea quality from Rishi is hard to beat and emboldens me to try new things.
buff.ly/TkEbz4s
Rishi Tea & Botanicals
Rishi Tea & Botanicals is an online tea shop with a wide variety of loose leaf, sachet teas, tea gifts, teaware, and botanical ingredients. We are a Direct Trade importer of premium, organic teas and…
buff.ly
January 9, 2026 at 9:26 PM
Today I'm I enjoying my Golden Yunnan tea from Rishi, similar to English Breakfast tea but earthier and more flavorful.
I also got samples of their Pu'er and Wild Thai teas. The tea quality from Rishi is hard to beat and emboldens me to try new things.
buff.ly/TkEbz4s
I also got samples of their Pu'er and Wild Thai teas. The tea quality from Rishi is hard to beat and emboldens me to try new things.
buff.ly/TkEbz4s
Welcome to Trump's America. Drink as much as you want, because you're either getting deported or killed. 🇺🇸
January 9, 2026 at 7:50 AM
Welcome to Trump's America. Drink as much as you want, because you're either getting deported or killed. 🇺🇸
Who would have thought that hiring and arming a bunch of MAGA thugs to be unrestrained, masked immigration bounty hunters would lead to the murder of citizen protesters? 🙄
January 9, 2026 at 12:07 AM
Who would have thought that hiring and arming a bunch of MAGA thugs to be unrestrained, masked immigration bounty hunters would lead to the murder of citizen protesters? 🙄
Running my own business has given me new respect for corporate bookkeepers who used to chase me around for expense receipts. 😩
January 8, 2026 at 6:15 PM
Running my own business has given me new respect for corporate bookkeepers who used to chase me around for expense receipts. 😩
Really hoping I can join RBQ in Austin this March with a snazzy new talk about cool JRuby use cases! The CFP closes tomorrow, don't miss out!
rbqconf.com
rbqconf.com
RBQ Conf
RBQ Conf is a regional Ruby gathering where code meets community, with meaty talks, saucy insights, and plenty of time to connect. Coming to Austin, TX on March 26 & 27, 2026.
rbqconf.com
January 6, 2026 at 7:02 PM
Really hoping I can join RBQ in Austin this March with a snazzy new talk about cool JRuby use cases! The CFP closes tomorrow, don't miss out!
rbqconf.com
rbqconf.com
Inspired by Maciej's work in buff.ly/Pp5PKvT, I've attempted to integrate into JRuby a Java implementation of Daniel Lemire's fast float parsing. Early results are as much as 16x faster than the crusty old impl we currently have!
Use FastDoubleParser where appropriate by headius · Pull Request #9150 · jruby/jruby
This hooks up the FastDoubleParser project to our internal float parsing logic, excluding cases that are not 7-bit ASCII or which contain underscore characters (not currently allowed by FDP, see wr...
buff.ly
December 28, 2025 at 6:10 AM
Inspired by Maciej's work in buff.ly/Pp5PKvT, I've attempted to integrate into JRuby a Java implementation of Daniel Lemire's fast float parsing. Early results are as much as 16x faster than the crusty old impl we currently have!
Not sure which job is more repellant.
December 28, 2025 at 1:00 AM
Not sure which job is more repellant.
If I were to do a 1.5 hour workshop on JRuby, what would you most want to learn? Performance and optimization? Deploying Ruby apps on Java servers? Calling into other libraries on the JVM? JVM tools for profiling and monitoring? Hacking on JRuby itself?
December 26, 2025 at 4:39 AM
If I were to do a 1.5 hour workshop on JRuby, what would you most want to learn? Performance and optimization? Deploying Ruby apps on Java servers? Calling into other libraries on the JVM? JVM tools for profiling and monitoring? Hacking on JRuby itself?
I'm super excited to peak here for the first time and meet the local Ruby community! We will have a big new JRuby release by then with 4.0 compatibility and a bunch of optimizations.
Psst... see this gift under the Christmas tree? Let's unbox it 🎄
@headius.bsky.social joins us at #wrocloverb to show how you can level up your Ruby with JRuby - bringing true parallelism, pauseless garbage collection, and JIT optimizations to your Rails apps.
This one’s a real treat! 🎁
@headius.bsky.social joins us at #wrocloverb to show how you can level up your Ruby with JRuby - bringing true parallelism, pauseless garbage collection, and JIT optimizations to your Rails apps.
This one’s a real treat! 🎁
December 24, 2025 at 11:01 PM
I'm super excited to peak here for the first time and meet the local Ruby community! We will have a big new JRuby release by then with 4.0 compatibility and a bunch of optimizations.
A JRuby user upgrading an old app recently filed a bunch of bugs about poor perf versus CRuby. In almost every case, it was an optimization or logic change we never knew about, and once added JRuby is faster. If something isn't as fast in JRuby as in CRuby, it's a bug. Report it!
December 20, 2025 at 7:33 PM
A JRuby user upgrading an old app recently filed a bunch of bugs about poor perf versus CRuby. In almost every case, it was an optimization or logic change we never knew about, and once added JRuby is faster. If something isn't as fast in JRuby as in CRuby, it's a bug. Report it!
I would bet money that Google et al have been dumbing down their existing non-LLM services to force people to use their LLMs. Now that Gemini is offered to replace Google Assistant, the latter has become FAR worse, failing simple queries and commands. Class-action suit incoming?
December 18, 2025 at 8:17 PM
I would bet money that Google et al have been dumbing down their existing non-LLM services to force people to use their LLMs. Now that Gemini is offered to replace Google Assistant, the latter has become FAR worse, failing simple queries and commands. Class-action suit incoming?
I just tried to use ChatGPT to generate a switch to compare a byte[] with a set of strings, switched on the length of the string and then equality checks. The code looked right, except all of the sizes were totally wrong.
Lesson learned: don't use LLMs for anything numeric.
Lesson learned: don't use LLMs for anything numeric.
December 16, 2025 at 11:23 PM
I just tried to use ChatGPT to generate a switch to compare a byte[] with a set of strings, switched on the length of the string and then equality checks. The code looked right, except all of the sizes were totally wrong.
Lesson learned: don't use LLMs for anything numeric.
Lesson learned: don't use LLMs for anything numeric.
I think I need to reset my Duolingo Chinese course. 😞 Although I studied for two years at University, Duolingo has evolved over the years and I was unwillingly grandfathered into a very high level. It will be too easy for a while, but my character comprehension needs a reboot.
December 16, 2025 at 5:37 PM
I think I need to reset my Duolingo Chinese course. 😞 Although I studied for two years at University, Duolingo has evolved over the years and I was unwillingly grandfathered into a very high level. It will be too easy for a while, but my character comprehension needs a reboot.
I'm having trouble adopting this new LLM regime. What happens when a developer you rely on produces bad code one time out of ten? How about one time out of a hundred, but it's a severely critical bug? Who's going to find these issues after I'm gone?
December 10, 2025 at 9:53 AM
I'm having trouble adopting this new LLM regime. What happens when a developer you rely on produces bad code one time out of ten? How about one time out of a hundred, but it's a severely critical bug? Who's going to find these issues after I'm gone?
Too many projects I wish I had time for.
* A (new) impl of Python, Go, or Rust-like language for JVM.
* Ruby library for emitting Project Babylon CUDA code.
* Ruby LSP plug-in for JRuby Java integration.
* New JRuby SSL library based on JDK crypto support.
I need a team.
* A (new) impl of Python, Go, or Rust-like language for JVM.
* Ruby library for emitting Project Babylon CUDA code.
* Ruby LSP plug-in for JRuby Java integration.
* New JRuby SSL library based on JDK crypto support.
I need a team.
December 10, 2025 at 6:12 AM
Too many projects I wish I had time for.
* A (new) impl of Python, Go, or Rust-like language for JVM.
* Ruby library for emitting Project Babylon CUDA code.
* Ruby LSP plug-in for JRuby Java integration.
* New JRuby SSL library based on JDK crypto support.
I need a team.
* A (new) impl of Python, Go, or Rust-like language for JVM.
* Ruby library for emitting Project Babylon CUDA code.
* Ruby LSP plug-in for JRuby Java integration.
* New JRuby SSL library based on JDK crypto support.
I need a team.
The Vector API for Java will have its 11th "incubator" release in JDK 16. Starting to wonder if we need Daenerys Targaryen to carry it into a funeral pyre before that egg will hatch. 🐲🐣
December 4, 2025 at 8:49 PM
The Vector API for Java will have its 11th "incubator" release in JDK 16. Starting to wonder if we need Daenerys Targaryen to carry it into a funeral pyre before that egg will hatch. 🐲🐣
Reposted by Charles Oliver Nutter
JDK 26 has been branched from the main line and is now in Rampdown Phase One: mail.openjdk.org/pipermail/jd...
openjdk.org/projects/jdk/26/
#JDK26 #OpenJDK #Java
openjdk.org/projects/jdk/26/
#JDK26 #OpenJDK #Java
mail.openjdk.org
December 4, 2025 at 6:53 PM
JDK 26 has been branched from the main line and is now in Rampdown Phase One: mail.openjdk.org/pipermail/jd...
openjdk.org/projects/jdk/26/
#JDK26 #OpenJDK #Java
openjdk.org/projects/jdk/26/
#JDK26 #OpenJDK #Java
Now what do I do? 😩
December 4, 2025 at 6:35 PM
Now what do I do? 😩
This is what happens when you torture a prickly pear with barely enough sun and water to survive.
December 4, 2025 at 5:46 PM
This is what happens when you torture a prickly pear with barely enough sun and water to survive.
Why not use Java's instanceof patterns to null-check values in the middle of an `if` statement?
Non-null variable declaration in Java using instanceof patterns
Ever since JRuby 10 upgraded to Java 21, I’ve been re-learning Java with all the excellent language enhancements of the past decade. One of my favorites has to be the instanceof pattern matching…
buff.ly
December 4, 2025 at 8:47 AM
Why not use Java's instanceof patterns to null-check values in the middle of an `if` statement?
Somebody tell me why I shouldn't use instanceof pattern matching in Java to perform a null check plus variable declaration and assignment all at once:
if (obj.getValue() instanceof Value value) {
// use value
} else {
// it's null
}
if (obj.getValue() instanceof Value value) {
// use value
} else {
// it's null
}
December 4, 2025 at 4:54 AM
Somebody tell me why I shouldn't use instanceof pattern matching in Java to perform a null check plus variable declaration and assignment all at once:
if (obj.getValue() instanceof Value value) {
// use value
} else {
// it's null
}
if (obj.getValue() instanceof Value value) {
// use value
} else {
// it's null
}
I'm holding out for AI contact lenses.
November 26, 2025 at 5:05 PM
I'm holding out for AI contact lenses.