shared: Allows sharing of a published Web module between Web sites, when a Web site is defined by a particular pairing of a protocol and a port. Supported values are "true" and "false" (default). Sharing implies the sharing of everything that makes up a Web application, including sessions, servlet instances, and context values. An example is to share a Web application in OC4J standalone between an HTTP site and an HTTPS site at the same context path, when SSL is required for some but not all the communications. (Performance is improved by encrypting only sensitive information, rather than all information.)
If an HTTPS Web application is marked as shared, its session tracking strategy reverts from SSL session tracking to session tracking through cookies or URL rewriting. This could possibly make the Web application less secure, but may be necessary to work around issues such as SSL session timeouts not being properly supported in some browsers.