docx4j parent
· docx4j is a library which helps you to work with the Office Open
XML file format as used in docx
documents, pptx presentations, and xlsx spreadsheets.
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 docx4j-parent-8.3.9.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.