Atom
· Atom is the world’s most advanced software platform for building complex
applications and redefining what people can do without programming
knowledge.
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 atom-1.0.0.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.