Google's Closure Library
· This is a helpful packaging of source code for JavaScript
developers using Maven. This is published on schedule, so not
all subversion revisions are available. Just those that are
available when the bundling process begins.xxx
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 closure-library-99cd91.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.