JD-GUI

JD‑GUI is a standalone graphical utility that reads Java .class files and presents the reconstructed source code. It supports a variety of container formats—including JAR, WAR, EAR, AAR, KAR, JMOD and ZIP—allowing users to browse methods, fields and class hierarchies directly within the interface. The viewer highlights syntax with color coding and can display the line of code referenced in stack‑trace logs, facilitating quick analysis of compiled bytecode.

The tool is built on the JD‑Core library, which reconstructs Java source from bytecode produced by many compiler versions, from JDK 1.1 up through recent releases such as JDK 10 and newer. JD‑Core also handles Java 5 language features like annotations, generics and enums, ensuring that decompiled output reflects modern code constructs.

JD‑GUI is intended for developers, reverse engineers and anyone needing to inspect or recover Java source when original files are unavailable. It runs on macOS, Windows and Linux, and is distributed under the GPLv3 license as an open‑source project.