JasperReports Grails Plugin
· This plugin adds easy support for launching JasperReports from GSP pages and provides services and controllers for generating reports.
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 jasper-2.2.1.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.