Translation and Serialization Toolkit
· A toolkit that aids in the conversion between two Java objects, primiarly for use with coverting between an input Java object and a application Java object.
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 parent-3.2.1.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.