Apache Commons Weaver Build Tools
· Provide common setup, from http://maven.apache.org/plugins/maven-checkstyle-plugin/examples/multi-module-config.html
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 commons-weaver-build-tools-2.0.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.