Not every method that gets called by an application is compiled.
The Just-In-Time (JIT) improves the performance of Java applications by compiling platform-neutral Java bytecode into native machine code at run time. The components that make up Eclipse OpenJ9 are described in the following sections: At the OpenJ9 project, an extra layer of code adds the language semantics to provide a runtime environment for Java applications. Įclipse OpenJ9 embeds Eclipse OMR, which provides core runtime components that can be used to build runtime environments for different programming languages. Compared to Oracle's HotSpot VM, OpenJ9 touts higher start-up performance and lower memory consumption at a similar overall throughput. The same version of the JVM can be used in OpenJDK 8 and later releases, which means that many features and improvements can be exploited by applications that run on different versions of Java. The Eclipse OpenJ9 JVM is fully compliant with the Java JVM specification. At the Eclipse Foundation, OpenJ9 is classified as an incubator project, with the first release, v0.8.0, delivered in 2018.
IBM continue to be actively involved in the project and continue to put this Java VM at the core of many software offerings. In 2017, J9 became an Eclipse Foundation project under the name Eclipse OpenJ9. The J9 JVM became the runtime engine for many of IBM's enterprise middleware products, where it has built its reputation for high performance, scalability, and reliability. K→J (a backward step) because the developers believed that Smalltalk was better than Java, but 8→9 (a forward step) because the new VM would be better than before. The name J9 evolved from the naming convention for the Smalltalk source code, K8. However, when the Java language emerged as a leading language for the enterprise market, the existing Smalltalk VM was adapted to process Java bytecodes instead. IBM purchased OTI in 1996 for their Smalltalk expertise and products. OpenJ9 can trace its roots back to the ENVY/Smalltalk product developed by Object Technology International (OTI). Įxtensive configuration options ensure that the JVM can be tuned to satisfy the requirements of a wide range of Java applications, from complex enterprise applications that run on mainframe hardware to short-lived applications that run on container-based cloud services. OpenJ9 is also a component of Open Liberty. OpenJ9 is also a core component of the IBM developer kit, which is embedded in many IBM middleware products, including WebSphere Application Server and Websphere Liberty. OpenJ9 can be built from source, or can be used with prebuilt binaries available at the AdoptOpenJDK project for a number of platforms including Linux and Windows. GNU General Public License, version 2 with the GNU Classpath Exception GNU General Public License, version 2 with the OpenJDK Assembly Exception Įclipse OpenJ9 (previously known as IBM J9) is a high performance, scalable, Java virtual machine (JVM) implementation that is fully compliant with the Java Virtual Machine Specification.