PearColator is a DBT built around an existing dynamic optimizing compiler and adaptive compilation framework. It is written in Java. It has a safe and portable memory model, the cost of which can be optimized away by code motion, extended array SSA transformations and other optimizations (the Jikes RVM has a clean and simple intermediate representation making it ideal for creating optimizations - Java is well known as an excellent develoment language). PearColator is cleanly written in Java, and should be portable to other JVMs at little cost. PearColator optimizes itself in parallel to its execution. As part of the Jamaica project parallelisation optimizations have been created and are being tested for PearColator. Java's exception model allows hardware exceptions to be precisely and accurately simulated in the presence of optimizing compiler optimizations.