javax.servlet(Servlet and JavaServer Pages API Documentation) javax.servlet
Interfaces 
Filter
FilterChain
FilterConfig
RequestDispatcher
Servlet
ServletConfig
ServletContext
ServletContextAttributeListener
ServletContextListener
ServletRequest
ServletResponse
SingleThreadModel
Classes 
GenericServlet
ServletContextAttributeEvent
ServletContextEvent
ServletInputStream
ServletOutputStream
ServletRequestWrapper
ServletResponseWrapper
Exceptions 
ServletException
UnavailableException