How to Decompile a JAR File (Step-by-Step Guide)

Learn how to decompile a JAR file and recover readable Java source code from .class bytecode — using online tools and command-line decompilers.

When Do You Need to Decompile a JAR?

Method 1: Decompile a JAR Online (Fastest)

Method 2: Decompile a Single Class Online

Method 3: CFR (Command-Line, Recommended Offline)

Method 4: Use an IDE With Built-In Decompilation

Method 5: Other Command-Line Decompilers

Understanding the Output

Legal Considerations

Summary