A Session Initiation Protocol (SIP) application is a group of servlets, resources and source files, that can be managed as a single unit. A Servlet ARchive (SAR) file is a packaged SAR application. You can use SAR files to import a SIP application into a server.
In addition to project resources, the SAR file includes a SIP deployment descriptor file. The SIP deployment descriptor is an Extensible Markup Language (XML) file that contains deployment information, Multipurpose Internet Mail Extension (MIME) types, session configuration details, and other settings for a SIP application. The SIP deployment descriptor file (sip.xml) provides information about the SAR file and can be shared with the developers, assemblers, and deployers in a Java 2 Platform, Enterprise Edition (J2EE) environment.