Bytecode Viewer (BCV) is an all-in-one, lightweight Java and Android reverse engineering suite that allows you to decompile, disassemble, and inspect compiled Java binaries. It integrates multiple open-source tools under a single graphical interface, making it highly effective for code analysis, debugging, or auditing. 🚀 Getting Started
Launch the Application: Download the executable .jar file from the Official Bytecode Viewer GitHub Repository. Run it from your terminal using: java -jar Bytecode-Viewer-2.10.x.jar Use code with caution.
Import Target Application: Drag and drop your target file directly into the Bytecode Viewer interface. It natively supports: Java Files: .class, .jar, .war Android Files: .apk, .dex, .xapk 🔍 Viewing and Analyzing Code
Once loaded, Bytecode Viewer parses the file structure and displays a file navigator panel on the left. Side-by-Side Decompilation
You can view multiple decompilers side-by-side to cross-reference code logic when one tool fails or produces confusing outputs. Navigate to View Pane > Select View 1, View 2, or View 3.
Choose your preferred built-in decompilers from the drop-down menu above each pane. BCV includes 6 decompilers:
CFR & Procyon: Excellent for modern Java syntax (lambdas, generics, switches).
FernFlower: The highly accurate engine utilized by IntelliJ IDEA.
JADX & JD-GUI: Fantastic for general reverse engineering and Android binaries. Krakatau: Heavily focused on raw bytecode precision. Disassembling to Raw Bytecode
If an application is heavily obfuscated, standard Java decompilers might crash or output broken source code. In this scenario, switch a view pane to a Disassembler (such as Krakatau or Smali/BakSmali). This exposes the exact stack-based instructions (e.g., ldc, invokevirtual, istore) running on the JVM.
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