Codehaus Cargo
· Cargo is a thin wrapper that allows you to manipulate various type of application containers (J2EE, Java EE, Jakarta EE and others) in a standard way.
Download JD-GUI to open JAR file and explore Java source code file (.class .java)
Click menu "File → Open File..." or just drag-and-drop the JAR file in the JD-GUI window codehaus-cargo-1.10.9.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.