Many free Java VMs use GNU Classpath as their class library. With the release of OpenJDK these VMs have another free, and mature library alternative. Porting a GNU Classpath based VM to OpenJDK is, however, non-trivial as the VM interfaces of the libraries are substantially different.

This talk will discuss the port of JamVM to the OpenJDK library. It will provide a brief overview of the library interfaces and will highlight several difficulties encountered due to mismatches in library/VM responsibilities.

The talk will be of particular interest to other runtime engineers thinking about doing a port to OpenJDK. However, it should be of interest to anybody who wishes to learn more about Java runtime internals, and the roles that the VM and class libraries play.