How to Obfuscate a JAR File (ProGuard Guide)

Obfuscate a Java JAR with ProGuard: config file, keep rules for main classes and reflection, the mapping file, and how to check the result by decompiling it online.

Step 1: Look at What a Decompiler Sees Today

Step 2: Write a ProGuard Configuration

Step 3: Run ProGuard

Step 4: Keep What Must Not Be Renamed

Step 5: Check the Obfuscated JAR

Step 6: Keep the Mapping File

Before You Obfuscate a Minecraft Mod

Summary