Download Recaf – Modern Java Bytecode Editor and Reverse Engineering Tool

Recaf is a free, open-source Java bytecode editor designed for reverse engineering, analyzing, and modifying compiled Java applications. It provides a modern graphical interface for opening JAR and CLASS files, browsing their contents, editing bytecode instructions, decompiling classes to readable Java source, and recompiling changes back into the JAR.

Unlike raw bytecode editors that require deep knowledge of the JVM instruction set, Recaf integrates the CFR decompiler to show human-readable Java source alongside the bytecode view, and allows editing at the source level with changes compiled back to bytecode automatically. This makes it accessible for Java developers who need to patch or analyze third-party libraries, debug obfuscated code, or perform security research on Java applications.

Recaf supports class renaming, field and method editing, adding and removing members, and editing constant pool entries. Its plugin system allows extending functionality, and it handles modern Java class formats including those compiled with Java 17, 21, and beyond.

Key Features

• JAR and CLASS file editor – Open, browse, modify, and save compiled Java JAR or CLASS files directly.
• Integrated decompiler – Decompile bytecode to readable Java source using CFR, Procyon, or other decompilers.
• Source-level editing – Edit decompiled Java source and recompile changes back to bytecode in-place.
• Bytecode instruction editor – View and edit raw JVM bytecode instructions, opcodes, and operands.
• Rename and refactor – Rename classes, fields, and methods across the entire JAR with automatic reference updating.
• Plugin support – Extend Recaf with plugins for additional decompilers, analyzers, and workflow tools.
• Modern Java support – Handles class files compiled with Java 8 through the latest Java LTS releases.

How to Install

1. Ensure Java 11 or higher is installed on your system.
2. Download the Recaf JAR file from the link below.
3. Run Recaf with java -jar recaf.jar from the command line, or double-click the JAR if Java is associated with .jar files on your system.
4. Open a JAR or CLASS file via File > Open to begin browsing and editing its contents.
5. Navigate the class tree, select a class to view its decompiled source or bytecode, make edits, and export the modified JAR via File > Export.