Open Source Obfuscators in Java

yGuard is a free open-source Java bytecode obfuscator and shrinker. It renames classes and methods and removes dead code; works as an Ant task with Maven/Gradle.

ProGuard shrinks and obfuscates Java and Kotlin bytecode: removes unused classes, fields, and methods and renames the rest. Standard optimizer for Android and desktop JARs; GuardSquare maintains it and offers ProGuardCORE.

RetroGuard obfuscates Java bytecode by stripping debug info and renaming classes, methods, and fields. It produces verifiable bytecode and can reduce JAR size. Original site gone; code available via GitHub fork and Maven.

jarg shrinks and optimizes JARs by removing unused classes, methods, and debug info and by renaming private members. It can reduce size and speed loading; output is harder to reverse-engineer.

JavaGuard is a bytecode obfuscator that renames and transforms classes and methods to hinder decompilation and reverse engineering, with Ant integration.

JODE provides a Java decompiler and a class-file optimizer. The optimizer renames classes/methods/fields, removes debug info and dead code, and optimizes local variables; behavior is script-controlled.