SIP Servlet API
· The SIP Servlet API defines a high-level extension API for SIP servers. It enables SIP applications to be deployed and managed based on the servlet model.
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 sip-api-1.0.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.