This JPOX sub-project provides a byte-code enhancer for use in Java Data Objects (JDO). All current JDO implementations rely on the use of enhancement of the users classes that are to be persisted. This enhancement (or instrumentation) is performed using an enhancer. JPOX provides its own byte-code enhancer. The enhancer relies on the JPOX Core which provides the definition of MetaData defining which classes are to be persistable (which classes need enhancing). It also relies on the BCEL byte code modification library. The org.jpox.enhancer.conf package takes the MetaData definition defined in JPOX Core and extends it slightly for enhancement. The org.jpox.enhancer.method package provides the byte-code modification capability, using BCEL to achieve this.