Johannes Bechberger
LightNews LightNews
banner
mostlynerdless.de
Johannes Bechberger
@mostlynerdless.de
640 followers 97 following 150 posts
OpenJDK hacker at SapMachine, works on hello-ebpf for fun
Posts Replies Media Videos
mostlynerdless.de
Having a last name that comes early when sorted alphabetically sometimes has its advantages:
November 13, 2025 at 7:09 AM
mostlynerdless.de
Sneak peek into my upcoming blog post:
Plot of sample loss and memory consumption vs queue size in the new CPU-time sampler of JDK 25
August 22, 2025 at 10:22 AM
mostlynerdless.de
RIP Java Applets. You made Java popular and helped it grow to what it is today.

JEP 504: Remove the Applet API has been proposed to target (openjdk.org/jeps/504), so there will be no more applets with the next JDK (JDK 26).
Thombstone with "RIP Applet" written on it.
July 7, 2025 at 2:53 PM
mostlynerdless.de
I just updated the JFR events collection (sapmachine.io/jfrevents). It now includes JDK 25 and JDK 26 with my CPUTimeSample event:
June 10, 2025 at 12:44 PM
mostlynerdless.de
June 4, 2025 at 10:10 PM
mostlynerdless.de
Well...
mgronlun left a comment: | am approving this PR for the following reasons: 1. We have reached a state that is "good enough" - | no longer see any fundamental design issues that can not be handled by follow-up bug fixes. 2. There are still many vague aspects included with this PR, as many has already pointed out, mostly related to the memory model and thread interactions - all those can, and should, be clarified, explained and exacted post-integration. 3. The feature as a whole is experimental and turned off by default. 4. Today is the penultimate day before JDK 25 cutoff. To give the feature a fair chance for making JDK25, it needs approval now. Thanks a lot Johannes and all involved for your hard work getting this feature ready. Many thanks Markus
June 4, 2025 at 12:30 PM
mostlynerdless.de
I needed a QR code for a presentation and found nythrox.github.io/halftone-qrc.... It allows you to add a picture to your QR code in a few different ways.
May 28, 2025 at 12:52 PM
mostlynerdless.de
And in what outfit are you giving your talks?
May 13, 2025 at 10:31 AM
mostlynerdless.de
The good old days of console apps on your phone, it even supports touch:
Terminal app on Android showing a prompt
May 8, 2025 at 12:47 PM
mostlynerdless.de
My favourite picture from @amsterdam.voxxeddays.com
Me pointing at something
April 8, 2025 at 2:33 PM
mostlynerdless.de
12 am is midnight @officialgrammarly.bsky.social :D
February 25, 2025 at 7:50 AM
mostlynerdless.de
When all you do is wait. Thanks to perf and @firefoxperformance.bsky.social FirefoxProfiler I found why my code didn't work (profiler.firefox.com/public/a6s9g...):
Flamegraph showing the my code just waited to get a lock
February 20, 2025 at 8:47 AM
mostlynerdless.de
You can see me speak on mostlynerdless.de/blog/2024/05... at @amsterdam.voxxeddays.com in April:
Speaker announcement panel of Johannes Bechberger at VoxxedDays Amsterdam. The title of the talk is "Who instruments the instrumenters?"
February 19, 2025 at 2:29 PM
mostlynerdless.de
I had a missed connection in Frankfurt. So here's a picture of the empty upper level of the Frankfurt Airport train station at 7am
Upper level of the Frankfurt Airport train station
February 1, 2025 at 9:33 AM
mostlynerdless.de
On my way to @fosdem.bsky.social to give three talks today (see fosdem.org/2025/schedul...)
Karlsruhe main station at night
February 1, 2025 at 3:54 AM
mostlynerdless.de
On my way to @fosdem@fosstodon.org to give three talks today (see fosdem.org/2025/schedul...)
Karlsruhe main station at night
February 1, 2025 at 3:52 AM
mostlynerdless.de
I'm on the train to Malmö to give my first talk of the year, talking on Linux scheduler, eBPF and Java
January 20, 2025 at 7:12 AM
mostlynerdless.de
And I'm busy preparing the talk:
January 19, 2025 at 2:00 PM
mostlynerdless.de
I did a few conferences last year, I guess:
January 8, 2025 at 10:32 AM
mostlynerdless.de
The following is the only CPU arch specific code for JFR:
November 20, 2024 at 9:36 AM
mostlynerdless.de
TIL: The zero VM doesn't support JFR
November 19, 2024 at 11:37 AM
mostlynerdless.de
Many JFR events don't have any descriptions, so sapmachine.io/jfrevents/ now includes code snippets from the events usage in OpenJDK:
October 31, 2024 at 6:47 AM