support protocol

All servlet containers must support HTTP as a protocol for requests and responses, but additional request/response-based protocols such as HTTPS (HTTP over SSL) may be supported. The required versions of the HTTP specification that a container must implement are HTTP/1.0 and HTTP/1.1. Because the container may have a caching mechanism described in RFC2616(HTTP/1.1), it may modify requests from the clients before delivering them to the servlet, may modify responses produced by servlets before sending them to the clients, or may respond to requests without delivering them to the servlet under the compliance with RFC2616.