Mutability Detector is a lightweight static analysis tool for Java which allows you to unit test for immutability. Using immutable objects is regarded as improving readability of your Java code, and greatly simplifying multithreaded code. However, without language support, it's all to easy to render classes mutable, and introduce the potential for subtle, hard to detect bugs. Mutability Detector gives developers a way to write immutable classes, and help keep them immutable.

Mutability Detector uses and depends on several free, open-source Java libraries, such as Objectweb ASM. Also, being able to look at the source of the JDK, has greatly helped in improving the analysis.

The audience will learn of a simple little utility that may just help them in their day-to-day development of Java. People can help out in the usual FLOSS way - using it, reporting bugs, giving feedback (especially the ways in which I suck).