Shrinks and obfuscates, with template-based configuration. Comes with an Ant task, a J2ME WTK plugin, and a tool to de-obfuscate stack traces. [Open source, GPL]

Highly-configurable Java bytecode obfuscator with support for Java 2, reflection and scripting. [Open Source, LGPL]

Tool for the Java bytecode protection and feature driven license management. The 'Saffeine' engine uses strong cryptography algorithms to obfuscate unlicensed Java byte code. [Commercial]

Scrambles source code using nonsense names and stripping comments to disable reverse engineering. Works on large sets of files. [Commercial]

A Java class file obfuscator, that supports selective renaming, unused method and field removal, as well as bytecode obfuscation. [Shareware]

Java obfuscator with flow obfuscation, string literal encryption, scripting, Ant integration, incremental obfuscation, obfuscated line numbers, J2ME plugin and stack trace translation. Also removes unused classes, fields and methods. [Commercial]