The ServerContainer is the specialized view of the WebSocketContainer available in server-side deployments. There is one ServerContainer instance per websocket application. The ServerContainer holds the methods to be able to register server endpoints during the initialization phase of the application.

For websocket enabled web containers, developers may obtain a reference to the ServerContainer instance by retrieving it as an attribute named javax.websocket.server.ServerContainer on the ServletContext. This way, the registration methods held on this interface may be called to register server endpoints from a ServletContextListener during the deployment of the WAR file containing the endpoint.

WebSocket implementations that run outside the web container may have other means by which to provide a ServerContainer instance to the developer at application deployment time.

Once the application deployment phase is complete, and the websocket application has begun accepting incoming connections, the registration methods may no longer be called.