This chapter describes how to develop Session Initiation Protocol (SIP) Servlet applications that support concurrency in Oracle Communications Converged Application Server. It also explains ways to develop portable applications without concurrency issues.

Multiple Servlets executing simultaneously may have active access to shared resources like the SipSession and SipApplicationSession objects. These resources may also be accessed concurrently from ServletTimer objects, from other Java Platform, Enterprise Edition (Java EE) modules in a converged Java EE application, and by the SIP Servlet Container. Operations, such as updating values of session attributes, carried out by different threads on these objects can create concurrency issues, including deadlock, for some applications.