J9 is a Java Virtual Machine program developed by IBM. The J9 VM is the basis of multiple IBM Java offerings, including WebSphere Micro Edition, as well as the basis of all IBM Java Development kits since version 5. IBM has also made the J9 VM available to the Apache Harmony project for use in running their class libraries.The design of the J9 VM has been aimed at portability to different platforms, as well as scaling from mobile phones all the way to IBM System z mainframes.