Safe class sharing among Java processes

The execution of multiple, mutually distrusting applications or multiple instances of the same application for different users in a Java Virtual Machine (JVM) requires a form of multi-processing which protects the integrity of the JVM as well as the integrity of individual applications. Existing solutions protect processes by loading application classes in dedicated process class loaders and by allowing sharing of only the core Java classes between processes. These techniques are costly in terms of memory consumption, startup time and inter-domain communication. This paper describes a new approach which overcomes these limitations. It proposes a byte code transformation which allows the safe sharing of application classes between processes even in the presence of static fields. The feasibility of our approach is verified in a quantitative performance evaluation.