The next open source JVM. Built with @EclipseOMR.

Joined March 2017
40 Photos and videos
Check out the full JAVAPRO deep dive on OpenJ9 GC policies 👇 javapro.io/2026/05/21/openj9…
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We’re excited to announce the release of Eclipse OpenJ9 v0.59.0 🎉 Get it now at ibm.biz/GetSemeru and explore the latest improvements. Curious about OpenJ9 GC policies♻️? We’ve included a quick overview below with a deep-dive article coming soon. Stay tuned!
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We’re pleased to announce the availability of Eclipse OpenJ9 v0.58.0 which adds support for OpenJDK 26 🎉 A big thanks to IBM for building and distributing Semeru Runtimes Open Edition with this release. Downloads available here: ibm.biz/GetSemeru
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21 Jun 2024
As @mstoodle says, we're always keen to hear from our users and our community is really quite friendly :) . If you haven't arleady, join our slack instance at openj9.slack.com/join/shared…

My Eclipse @OpenJ9 and IBM Semeru Runtimes talk at JCON 2024, looking at adoption and things we're doing to improve! Thanks again to @jcon_conference for the opportunity to present in a movie theatre!!
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18 Jun 2024
Reminder that our community meeting is today at 10:30am ET if you want to drop by!
A great opportunity to learn more about the most recent Eclipse @OpenJ9 release and to directly meet and hear from the developers and technical leads behind this incredible project!
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13 Jun 2024
Eclipse @OpenJ9 recently announced the release of OpenJ9 v0.44.0 (April Quarterly refresh) OpenJ9 v0.45.0 (JDK22). Join us at the OpenJ9 community call on June 18, 10:30am EST as we discuss some of the new features that made it to the release. calendar.app.google/T3YKp8xT…

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12 Jun 2024
...and Eclipse @OpenJ9 of course :)
Replying to @MarkusKett
You can have a laugh at my own antics, including my amusing quest to get the demo right, starting at about 26:30 in that video. Oh, and you can learn a bit about @OpenLibertyIO, CRIU, InstantOn, IBM Semeru Runtimes, and (not enough yet?) ultra fast 21.8X faster Java startup !!!!!
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12 Jun 2024
Powered by the CRIUsupport in Eclipse @OpenJ9 !!
JCON2024 keynote with @MarkusKett on EclipseStore: simple, databaseless in-memory data processing. Up to 1000x faster queries, up to 99% cloud db cost savings. With @OpenLibertyIO InstantOn and Semeru Runtimes JDK, production ready EclipseStore cluster nodes start in milliseconds
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All feedback welcome!! We love to hear back from our users on stuff that goes well and on stuff we can make better!
Replying to @rmannibucau
Yes, C# originated from J (Microsoft Java). While Java adopted some ideas from C# which took the idea of Java, all OO programming languages share similar concepts. I'm impressed with OpenJ9. For better performance, I'll consider J9 since it avoids compile-time issues.
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Eclipse OpenJ9 retweeted
Honored to be speaking today about Cloud-Native Java at the Open Source North conference in beautiful St. Paul. Pls join me in ASC Room C at 1PM. #osn2024 @OpenLibertyIO @openj9 @SemeruRuntimes
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Eclipse OpenJ9 retweeted
Some references that might interest you or others using quarkus: blog.openj9.org/?s=Quarkus . Not sure what their support stance is, though.

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Eclipse OpenJ9 retweeted
@jcon_conference All three workshop sections showcase how Semeru Runtimes and Eclipse @openj9 use significantly (half to two thirds) less memory than e.g. Eclipse Temurin with the same heap size settings. I'd love to hear how the workshop works for you!
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Eclipse OpenJ9 retweeted
3rd (last) part of the workshop: see how the Semeru Cloud Compiler offloads @OpenJ9 JIT CPU and memory overheads. easy to deploy and enabled a 67% increase in the number of responses processed in the first minute for a JavaEE7 application running with just 1 CPU core and 200MB!
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Eclipse OpenJ9 retweeted
Workshop part 2: learn about @OpenLibertyIO and Semeru Runtime InstantOn by adding a single line to a Dockerfile to start a JavaEE ready server in 200-400ms with no Java language restrictions. Not using InstantOn? Your server workloads could be starting 10X-20X slower!
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Eclipse OpenJ9 retweeted
In part 1, learn about @OpenJ9's shared classes cache. See why @OpenLibertyIO uses it by default to save roughly 40% startup time v. Eclipse Temurin. Then learn how you can also easily cut ~50% from Tomcat startup with shared cache: on any platform with no language restrictions.
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28 May 2024
A great way to learn about how to use all our completely open source JVM technologies: 1) Shared Classes Cache (Java start in 50% of time), 2) InstantOn (Java start 10X-20X faster on Linux), and our JIT server (Cloud Compiler) that offloads JIT overheads to a remote JIT service!
Replying to @jcon_conference
@jcon_conference @IBMDeveloper @OpenLibertyIO @openj9 JCON2024 workshop "Java with Ultra Fast Startup and Remote JIT Compilation", see README.md to run in a container on your laptop. Includes pdf of my slides so it's a bit beefy: git clone github.com/mstoodle/jcon2024…
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21 May 2024
See openliberty.io/docs/latest/i… and eclipse.dev/openj9/docs/jits… for tips on how to reach ultra fast startup and offload JIT compilation overheads to an independent service!
16 May 2024
Replying to @simas_ch
Every Java developer try @openj9 IBM semeru runtime InstantOn and Jit Server features…
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Eclipse OpenJ9 retweeted
IBM Semeru Runtimes January update release, including the 0.43 release of Eclipse @OpenJ9 built into Java 8u402, 11.0.22, 17.0.10, and 21.0.2 is out! IBM hasn't published the release notes yet (they're coming!) but the @OpenJ9 project has 0.43 notes here: github.com/eclipse-openj9/op…
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