J9 VM reference

Reference information for the J9 virtual machine (VM).

This documentation covers the IBM J9 VM that was contributed to the open source Eclipse OpenJ9 project in September 2017. The longer-term goal is to host OpenJ9 documentation in the community, but until then, you can use the information in this reference to help you configure and tune the OpenJ9 VM.

J9 is a high performance, scalable, Java™ VM implementation, which is a core component of IBM® SDK, Java Technology Edition. At run time, the VM interprets the Java bytecode that is compiled by the Java compiler. The VM acts as a translator between the language and the underlying operating system and hardware. A Java program requires a specific VM to run on a particular platform, such as Linux®, z/OS®, or Windows.

This reference material provides detailed information about the sub-components of the J9 VM, together with configuration and tuning options. Information is also included about specific hardware features that the VM is designed to exploit for performance benefits.