Implementation Creator is an extension point that allows the persistence of interfaces. It is responsible for constructing persistent classes out of interfaces at runtime. The JPOX Enhancer plug-in has two ImplementationCreator implementations one using BCEL and the other using ASM. You must have the JPOX Enhancer plugin in the CLASSPATH together with either BCEL or ASM whichever you select. The ImplementationCreator is declared via the extension point org.jpox.implementation_creator and you can use the PMF setting org.jpox.implementationCreatorName to select which one you want to use. You can extend JPOX's capabilities using the plugin extension org.jpox.implementation_creator.