http://java-source.net/open-source/obfuscators/proguardProGuard is a free Java class file shrinker and obfuscator. It can detect and remove unused classes, fields, methods, and attributes. It can then rename the remaining classes, fields, and methods using short meaningless names. The resulting jars are smaller and harder to reverse-engineer.
JavaGuard is a general purpose bytecode obfuscator, designed to fit effortlessly into your regular build and testing process, providing peace of mind that your valuable Java code is more secure against decompilation and other forms of reverse engineering
JODE is a java package containing a decompiler and an optimizer for java. The optimizer transforms class files in various ways with can be controlled by a script file. It supports the following operations: * Renaming class, method, field and local names to shorter, obfuscated, or unique names or according to a given translation table * Removing debugging information * Removing dead code (classes, fields, methods) and constant fields * Optimizing local variable allocation
Allatori is a second generation Java obfuscator, which offers a full spectrum of protection for your intellectual property.
Although most second generation obfuscators allow for a worthy level of protection, we have developed a number of additional functions into Allatori to make reverse engineering the code nigh on impossible.
Allatori does not just obfuscate, it also minimizes application size, and boosts the speed, and all the while your code is unreadable by anyone but you and your team. Allatori, as every modern Java obfuscator, has full watermark functionality, allowing potential for proper licensing of your software!
If it is necessary for you to protect your software, and if you want to reduce both its size and processing time, Allatori obfuscator is for you.