The Java Compiler Kit is a straightforward implementation of a Java compiler, designed with extensibility in mind. In building the JKit compiler, the aims were: firstly, to help with teaching compilers by considering an implementation for a fully fledged language (Java), rather than a stripped-down imitation language; secondly, to aid research in programming languages, compilers and verification. With JKit you can easily prototype new extensions to the Java language, or implement completely new languages and compile them down to Java Bytecode.