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Johannes Bechberger

@mostlynerdless.de
680 followers 99 following 253 posts

OpenJDK hacker at SapMachine, works on hello-ebpf for fun

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Johannes Bechberger @mostlynerdless.de · 23/09/2026
The Code Remix Summit link seems to be broken... sessionize.com/ai-software-... is apparently what coderemix.ai references
sessionize.com
AI Software Factory Summit 2027: Call for Speakers
AI Code Factory Summit is built for the engineers who are done with surface-level AI hype. This is where developers, architects, and engineering leade...
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Johannes Bechberger @mostlynerdless.de · 16/09/2026
Probably because most people just read openjdk.org/projects/jdk... and the biggest change in this release is not mentioned
openjdk.org
JDK 27
This release is the Reference Implementation of version 27 of the Java SE Platform, as specified by JSR 402 in the Java Community Process.
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Johannes Bechberger @mostlynerdless.de · 16/09/2026
I'm covering topics most people missed :)
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Johannes Bechberger @mostlynerdless.de · 16/09/2026
☕️ Shape the future of Java. Join us on 1 October in Walldorf for a JCP Community Meetup with talks on Project Valhalla, Value Objects, and Java for AI. Meet Java community members, JCP representatives, and developers — and join the conversation. www.jug-da.de/2026/10/JCP-... #Java #JCP #OpenJDK
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Johannes Bechberger @mostlynerdless.de · 14/09/2026
The newly released Java 27 seems boring; the JDK only got some new defaults and refinements, but the most consequential change hides beneath the surface. Read all about the newest Java release in my blog post at mostlynerdless.de/blog/2026/09...
mostlynerdless.de
Java 27 is only boring on the surface. - Mostly nerdless
Java 27 seems to be boring; the JDK only got some new defaults, but the most consequential change is the removal of the JVM Compiler Interface.
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Reposted by Johannes Bechberger
BaselOne @baselone.bsky.social · 11/09/2026
Stop wasting hours on tests that never fail. 🧪 At #BaselOne26, @mostlynerdless.de shows how bytecode instrumentation can identify tests affected by code changes – so relevant tests run first and feedback comes faster. 👉 baselone.org#programm 🎟️ eventfrog.ch/BaselOne26 #BaselOne #SoftwareTesting
BaselOne 2026 session visual for the talk “Stop Wasting Hours on Tests That Never Fail” by Johannes Bechberger. The visual shows his portrait on a purple-to-red gradient background with a stylised Basel skyline. BaselOne takes place on October 14–15, 2026, at Markthalle Basel, Switzerland.
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Johannes Bechberger @mostlynerdless.de · 08/09/2026
What does GitHub's asset download counter really track? Not the full download, that's for sure. Read about my empirical investigation in my latest blog post: mostlynerdless.de/blog/2026/09...
mostlynerdless.de
What do GitHub download statistics really mean? - Mostly nerdless
What do GitHub release download statistics really count? Not what you assume, learn what I found in my empirical investigation and be confused.
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Johannes Bechberger @mostlynerdless.de · 01/09/2026
I arrived in Oslo for @javazone.bsky.social and just wanted to say thank you to the organizers, who were able to sort out any issues for the speakers within minutes (I was clumsy). It's the first conference I'll be speaking at as a newly minted Java Champion. Thanks for being awesome.
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Johannes Bechberger @mostlynerdless.de · 23/08/2026
Great tool, only nitpick, it is SapMachine, not "SAP Machine"
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Johannes Bechberger @mostlynerdless.de · 20/08/2026
There will be a blog post soon. But the main idea is to compress data structures you're not using. Graph datastructures seem to compress well with deflate. Not using a a GC also helped :)
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Johannes Bechberger @mostlynerdless.de · 20/08/2026
Have you seen github.com/parttimenerd..., my new tool for fast hprof-analysis?
github.com
GitHub - parttimenerd/hprof-analyzer: Fast Java heap dump analyzer, that emulates standard Eclipse MAT views with minimal memory in Rust
Fast Java heap dump analyzer, that emulates standard Eclipse MAT views with minimal memory in Rust - parttimenerd/hprof-analyzer
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Reposted by Johannes Bechberger
Jean-Philippe Bempel @jpbempel.bsky.social · 19/08/2026
Why is Arrays.fill 265 times slower on G1GC Good article from Krzysztof Ślusarski krzysztofslusarski.github.io/2026/08/19/g...
krzysztofslusarski.github.io
[Java][JVM][Tuning][Profiling][G1][JIT] Why is Arrays.fill 265 times slower on G1GC?
[Java][JVM][Tuning][Profiling][G1][JIT] Why is Arrays.fill 265 times slower on G1GC?
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Johannes Bechberger @mostlynerdless.de · 17/08/2026
Congrats.
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Johannes Bechberger @mostlynerdless.de · 05/08/2026
Yes, especially because other search engines like @duckduckgo.com and Bing find relevant resources and refrain from using a funny posts as their main resource.
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Johannes Bechberger @mostlynerdless.de · 31/07/2026
My fun little blog post titled "OpenJDK is faster than GraalVM Java*" became a major source for GoogleAI, and I don't know why: mostlynerdless.de/blog/2026/07...
mostlynerdless.de
I accidentally became Google AI's main resource for GraalVM vs OpenJDK - Mostly nerdless
My fun little blog post titled "OpenJDK is faster than GraalVM Java*", became a major source for GoogleAI, and I don't know why.
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Johannes Bechberger @mostlynerdless.de · 17/07/2026
Learn how to create a hand-drawn text reveal for header text with CSS and some clip-path magic in this week's blog posts: mostlynerdless.de/blog/2026/07...
mostlynerdless.de
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Johannes Bechberger @mostlynerdless.de · 07/07/2026
SAP joined the OpenJDK 15 years ago on the 14th of July 2011, contributing many ports, features, and ecosystem improvements. Let's celebrate: https:// mostlynerdless.de/blog/2026/07/07/celebrating-15-years-of-saps-involvement-in-the-openjdk/
mostlynerdless.de
Celebrating 15 years of SAP's involvement in the OpenJDK - Mostly nerdless
SAP joined the OpenJDK 15 years ago on the 14th of July, contributing many ports, features and ecosystem improvements. Let's celebrate.
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Johannes Bechberger @mostlynerdless.de · 20/05/2026
Welcome to the club
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Johannes Bechberger @mostlynerdless.de · 13/05/2026
See you in Krakow :)
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Johannes Bechberger @mostlynerdless.de · 11/05/2026
Want to make vegan waffles that don't rip or stick even when doing large badges on commercial-grade equipment? Here is a recipe that gives you proper heart waffles with inexperienced labor: mostlynerdless.de/blog/2026/05...
mostlynerdless.de
Vegan Waffle Recipe - Mostly nerdless
A vegan waffle recipe for waffles that don't riped apart or stick, using the power of food additives. Made for big events.
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Johannes Bechberger @mostlynerdless.de · 04/05/2026
I'm looking forward to speaking at this conference (and did you know that bagels came from Krakow?).
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Johannes Bechberger @mostlynerdless.de · 30/04/2026
Femtojar is a new tool and Maven plugin that reduces the size of your tool's JAR files using ProGuard, Zopfli, and a custom classloader. Read more on it in my latest blog post: mostlynerdless.de/blog/2026/04...
mostlynerdless.de
Honey, I shrank the JARs - Mostly nerdless
Femtojar is a new tool and Maven plugin to reduce the JAR files of your tools using ProGuard, Zopfli and a custom classloader.
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Johannes Bechberger @mostlynerdless.de · 24/04/2026
So if you're in the future in the area, feel free to message me. The only issue is that the people at the meet-up are usually more interested in the "how do you do open-source" part, and most often not in the deep-down specifics of your tool, as they are most likely not in your field of expertise.
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Johannes Bechberger @mostlynerdless.de · 24/04/2026
Would you be open to doing a remote session?
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Johannes Bechberger @mostlynerdless.de · 24/04/2026
It might be possible to invite someone from the community, but I don't have any budget, so the person would need to travel to WDF03 on their own accord.
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Johannes Bechberger @mostlynerdless.de · 22/04/2026
cc @qmacro.org
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Johannes Bechberger @mostlynerdless.de · 22/04/2026
Benefits for the speaker: A fun morning, bretzels, home-made croissants, and help in preparing your presentation by an experienced speaker (me).
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Johannes Bechberger @mostlynerdless.de · 22/04/2026
Dear bluesky: Does anyone here work at #SAP and want to show off a cool #opensource project they work on (at least partially) on company time? Then please message me, as I'm looking for people to tell cool stories in an SAP internal OSPO meetup in Walldorf. Please share...
A picture of a home-made croissant, which you can enjoy as a speaker at the open-source meetup
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Johannes Bechberger @mostlynerdless.de · 22/04/2026
Have fun and see you tomorrow
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Johannes Bechberger @mostlynerdless.de · 22/04/2026
I released a new version of ap-loader that wraps the newest async-profiler 4.4 version: github.com/jvm-profilin...
github.com
Release Loader for 4.4 (v13): async-profiler 4.4 · jvm-profiling-tools/ap-loader
ap-loader v13 Fix bug in AsyncProfilerLoader.getVersion() that caused it to return the same version number twice and crash The following is copied from the wrapped async-profiler release by Andre...
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Johannes Bechberger @mostlynerdless.de · 20/04/2026
JCmd allows you to quickly get information on an existing JVM, like thread-dumps. In this blog post, you'll learn to send commands programmatically: mostlynerdless.de/blog/2026/04...
mostlynerdless.de
Calling jcmd Commands Programmatically - Mostly nerdless
JCmd allows you to quickly get information on an existing JVM, like thread-dumps. In this blog post you'll learn to send commands programmatically.
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Johannes Bechberger @mostlynerdless.de · 20/04/2026
Honestly, it's surprising how easy it is to port a Java CLI into a tiny web-app with @graalvm.org: parttimenerd.github.io/jhserr/ It is far superior to running the CLI on a webserver, as these leads to all sorts of security problems and also privacy concerns (especially with redaction tools).
parttimenerd.github.io
hs_err Parser — Parse, Redact & Export
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Johannes Bechberger @mostlynerdless.de · 16/04/2026
A secret: Being able to submit a talk to JPrime on it is a good incentive to implement a feature :)
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Johannes Bechberger @mostlynerdless.de · 16/04/2026
Ever looked at a HotSpot error file and thought “nope”? I wrote a guide + built a VSCode highlighter and a browser redaction tool (using @graalvm.org). mostlynerdless.de/blog/2026/04...
mostlynerdless.de
On HotSpot Error Files and Useful Tools - Mostly nerdless
Learn all about HotSpot Error Files, a new syntax highlighter for VSCode and a redaction tool running directly in your browser.
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Johannes Bechberger @mostlynerdless.de · 15/04/2026
(I meant the compressed object headers)
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Johannes Bechberger @mostlynerdless.de · 15/04/2026
The main argument was, that you would need a really large heap and class space which you normally don't have on modern systems (cloud...). If I remember correctly we at SAP/SapMachine already use the compressed oops by default without any issues
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Johannes Bechberger @mostlynerdless.de · 15/04/2026
But it also reduces the number of classes that you can use (should be no problem for almost all applications)
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Johannes Bechberger @mostlynerdless.de · 14/04/2026
I just updated femtocli, my tiny (<50KB) CLI option parsing library. More bug fixes, better type conversions, and documentation: github.com/parttimenerd...
github.com
Release Release 0.4.0 · parttimenerd/femtocli
Added Builtin type converters for short, byte, and char fields ${COMPLETION-CANDIDATES} and ${DEFAULT-VALUE} placeholder expansion in @Parameters descriptions Changed Increased minimal JAR size ...
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Johannes Bechberger @mostlynerdless.de · 02/04/2026
Glad you liked it. It uses CSS transitions and an SVG :)
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Reposted by Johannes Bechberger
Ana-Maria Mihalceanu @ammbra1508.bsky.social · 02/04/2026
Probably the most cool visual explanation for HTTP/3 in #JDK26 by @lutskedev.bsky.social and Johannes Bechberger 🥳🥳🥳!!! #Java #JEP #VoxxedDaysAmsterdam
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Reposted by Johannes Bechberger
Lutske van der Meer @lutskedev.bsky.social · 02/04/2026
Join us today at 13:30 in zaal 11 @amsterdam.voxxeddays.com and hear why @mostlynerdless.de and I think that Java 26 is boring! #VDAMS26
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Johannes Bechberger @mostlynerdless.de · 31/03/2026
That's such a pity. Good luck with your job search.
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Johannes Bechberger @mostlynerdless.de · 17/03/2026
Java 26 is here, but it's boring. Nothing really exciting. But that's a good thing, as the boring stability is what made Java successful (co-written with @lutskedev.bsky.social): mostlynerdless.de/blog/2026/03...
mostlynerdless.de
Java 26 is boring, and that's a good thing - Mostly nerdless
Java 26 is here, but it's boring. Nothing really exciting. But that's a good thing, as the boring stability is what made Java successful.
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Johannes Bechberger @mostlynerdless.de · 16/03/2026
Come and win a "Java 26 is boring" t-shirt :)
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Johannes Bechberger @mostlynerdless.de · 12/03/2026
I know :) But lynx are just big cats.
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Johannes Bechberger @mostlynerdless.de · 12/03/2026
The cat is gorgeous :)
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Johannes Bechberger @mostlynerdless.de · 10/03/2026
Parsing JSON is not hard; we can easily build a parser that directly follows a (transformed) JSON grammar, creating femtojson in the process: mostlynerdless.de/blog/2026/03...
mostlynerdless.de
Writing a tiny JSON Parser - Mostly nerdless
Parsing JSON is not hard, we can easily build a parser that directly follows a (transformed) JSON grammar, creating femtojson in the process.
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Johannes Bechberger @mostlynerdless.de · 05/03/2026
When you come to the Java 26 talk, a custom-made "Java 26 is boring" shirt could be yours if you win our quiz.
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Johannes Bechberger @mostlynerdless.de · 02/03/2026
Looking forward to seeing you again :)
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Johannes Bechberger @mostlynerdless.de · 26/02/2026
See www.youtube.com/watch?v=I6vy...
youtube.com
The Simpsons - “Boring”
YouTube video by AreaEightyNine
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