As explained in the mail thread, the SIP Servlet API need to be simplified. Main aspects considered for this simplification are
1) Utilize Java EE 6 and 7 features to simplify the programming
Eg: Define JCDI custom scopes like SipSessionScoped or
SipApplicationSessionScoped, Use JCDI @Observes to listen to SIP
messages, Use AsyncContext of Servlet 3.0 for SIP etc.
2) Make the API more pluggable to add utilities/services in a
generic way. We only have B2BUaHelper now. Better modeling of B2bua.