JavaServer Pages 2.3
· This feature enables support for Java Server Pages (JSPs) that are written to the JSP 2.3 specification. This framework simplifies the construction of user interfaces. Enabling this feature also enables the Expression Language (EL) version 3.0 feature.
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 jsp-2.3-23.0.0.8.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.