Unleash the power of Java
Optimized to run Java™ applications cost-effectively in the cloud, Eclipse OpenJ9™ is a fast and efficient JVM that delivers power and performance when you need it most.
Optimized for the Cloud, for microservices and monoliths too!
Faster Startup
Faster Ramp-up, when deployed to cloud
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Our Story
Eclipse OpenJ9 is a high performance, scalable, Java virtual machine (JVM) implementation that represents hundreds of person-years of effort. Contributed to the Eclipse project by IBM, the OpenJ9 JVM underpins the IBM SDK, Java Technology Edition product that is a core component of many IBM Enterprise software products. Continued development of OpenJ9 at the Eclipse foundation ensures wider collaboration, fresh innovation, and the opportunity to influence the development of OpenJ9 for the next generation of Java applications.
Our supporters
The success of the OpenJ9 project is underpinned by the generosity of our supporters, to whom we would like to extend our thanks. This support comes in different forms; monetary, people, system, and data center resources. People resources help us to staff the planning, development, delivery, and support of OpenJ9 releases as well as pioneering new and innovative technologies. Dedicated systems and hosting services allow us to run automated build and test operations, which help ensure that quality and reliability is central to all our deliverables.
Join the conversation
Join us on Slack where you can ask questions and chat directly with our developers. Whether you simply have a question about using OpenJ9, an idea for improvement, or a problem you want to discuss, we'd love to hear from you.
Join OpenJ9 SlackLike all great open source projects, we have a vibrant and busy GitHub repository where you can create issues to explore ideas, request new features, or report any difficulties you are having.
See OpenJ9 IssuesParticipate in the Eclipse OpenJ9 project
Become a contributor
We welcome contributions to the project in all shapes and forms. If you are interested in JVM development, we'd love to hear your ideas and help you collaborate with us on the code base. There are other ways you can contribute too, such as working on our website and docs. Be a part of the project and share in our success!
Contributor GuideJoin community calls
Our regular calls are a great place to find out what is going on in the project. As well as discussing our release plans and development status, we often feature lightning talks by members of the community. For example, technical deep dives or overviews about new features. To see agendas and recordings, look in the Slack #planning channel.
Add to CalendarEclipse OpenJ9 version 0.47.0 released
September 2024
We're pleased to announce the availability of Eclipse OpenJ9 v0.47.0.
This release supports OpenJDK 23. For more information about supported platforms and OpenJDK versions, see Supported environments.
Other updates in this release include the following:
- The
-Xshareclassesoption automatically enables the-XX:+ShareOrphansoption.
To read more about these and other changes, see the OpenJ9 user documentation.
Eclipse OpenJ9 version 0.46.1 released
September 2024
We're pleased to announce the availability of Eclipse OpenJ9 v0.46.1.
This release supports OpenJDK 8, 11, 17, 21, and 22. For more information about supported platforms and OpenJDK versions, see Supported environments.
Other updates in this release include the following:
- OpenSSL native cryptographic support is added for the MD5 message digest algorithm, providing improved cryptographic performance.
- The OpenJ9 VM implementation supports measurement of the total memory allocation for all threads (
com.sun.management.ThreadMXBean.getTotalThreadAllocatedBytes()API). - The JITServer AOT caching feature is enabled by default at the JITServer server. The client still needs the
-XX:+JITServerUseAOTCacheoption, but it no longer relies on the presence of a shared class cache to take advantage of this feature. - A new option
-XX:[+|-]EnableExtendedHCRis added to enable or disable the extended Hot Code Replace (HCR) capability in the VM. - A new option
-XX:[+|-]ShareOrphansis added to enable class sharing from all class loaders, irrespective of whether the class loader implements the shared classes cache API. - A new option
-XdynamicHeapAdjustmentoption is added to automatically adjust the maximum and minimum Java heap sizes such that they are within the physical memory limitations on the checkpoint and restore systems.
To read more about these and other changes, see the OpenJ9 user documentation.
Performance highlights include the following:
- Performance of object and array allocation sequences on X86 is improved.
- Performance of array copying sequences on X86 is improved.
- VarHandle performance is improved.