Bytecode Viewer
Bytecode Viewer is a free desktop application for inspecting and decompiling Java bytecode, intended to support Java and Android reverse engineering.
What Bytecode Viewer is
Bytecode Viewer is a free desktop application for inspecting and decompiling Java bytecode, intended to support Java and Android reverse engineering. It opens Class, Jar, XAPK, APK, DEX, WAR, and JSP files, as well as image and text resources. The application includes six Java decompilers: Krakatau, CFR, Procyon, FernFlower, JADX, and JD-GUI. It also offers bytecode disassemblers, including Krakatau and Smali/BakSmali assemblers, and Android integrations such as Dex2Jar, Enjarify, and APKTool.jar for viewing Jar and APK resources.
Users can edit and compile Java and bytecode with its Java compiler, search statically, and use Java or JavaScript plugins to interact with loaded class files. Export options include runnable Jar, Zip, APK, and decompiled files as Zip. It is available for Linux, macOS, and Windows, and requires Java 8 or greater. The project is open source under GPL v3 Copyleft. Version 2.13.2 is marked in development; its command-line interface is not functional, and the project recommends v2.12 for CLI use.
Good
- Includes six Java decompilers.
- Supports Java and bytecode editing and compiling.
- Plugins can interact with loaded class files.
- Exports runnable Jar, Zip, APK, and decompiled files.
- Free and open source under GPL v3 Copyleft.
Watch out
- Requires Java 8 or greater.
- Version 2.13.2 is marked in development.
- Its command-line interface is not functional in 2.13.2.
- The project recommends v2.12 for CLI use.
Who it suits
Bytecode Viewer suits developers and reverse-engineering users who need to inspect Java or Android bytecode and resources. Its editing, scripting, and export tools may also fit users working with loaded class files.
Verdict
Bytecode Viewer combines decompilers, disassemblers, editing, search, plugins, and Android resource tools in one desktop application. Check the version limitation before relying on its command-line interface.
Plans and prices
From Bytecode Viewer's own pricing page, checked 7 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Bytecode Viewer | Free | 100% free · open source under GPL v3 Copyleft |
The facts
Each one read from Bytecode Viewer's own pages, with the date it was checked.
Where it runs
- Android integrations
- The maker lists Dex2Jar and Enjarify for APK/DEX support, and APKTool.jar for viewing Jar and APK resources.checked 7 Oct 2026
What it does
- Bytecode tools
- It includes three bytecode disassemblers, including the Krakatau and Smali/BakSmali assemblers.checked 7 Oct 2026
- Current release limitation
- The maker marks version 2.13.2 as in development and says its command-line interface is not functional, recommending v2.12 for CLI use.checked 7 Oct 2026
- Decompilers
- It includes six Java decompilers: Krakatau, CFR, Procyon, FernFlower, JADX, and JD-GUI.checked 7 Oct 2026
- Editing and compiling
- The product includes a Java compiler and supports Java and bytecode editing and compiling.checked 7 Oct 2026
- Export
- The maker lists export options including runnable Jar, Zip, APK, and decompiled files as Zip.checked 7 Oct 2026
- Intended users
- The project describes itself as a Java and Android reverse engineering suite designed to aid in the reversing process.checked 7 Oct 2026
- Operating systems
- The official site says it works with all operating systems and describes Windows file association support for .class, .dex, and .apk files.checked 7 Oct 2026
- Purpose
- Bytecode Viewer is a desktop application for analyzing and decompiling Java bytecode to help developers inspect and debug compiled code.checked 7 Oct 2026
- Requirements
- The maker lists Java 8 or greater as a requirement.checked 7 Oct 2026
- Search and plugins
- It provides advanced static search and a plugin system with Java and JavaScript scripting that can interact with loaded class files.checked 7 Oct 2026
- Security
- The project changelog says the Zip Slip exploit CVE-2022-21675 was patched in version 2.11.0.checked 7 Oct 2026
- Support
- The project directs users to GitHub issues for bugs and provides a discussion forum and Discord link.checked 7 Oct 2026
- Supported files
- It supports Class, Jar, XAPK, APK, DEX, WAR, JSP, image resources, and text resources.checked 7 Oct 2026
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