Servlet API

Servlet API consists of two important packages that encapsulates all the important classes and interface, namely :

ü  javax.servlet : The javax.servlet package contains many interfaces and classes that are used by the servlet or web container. These are not specific to any protocol.
ü  javax.servlet.http : The javax.servlet.http package contains interfaces and classes that are responsible for http requests only.

 Some Important Classes And Interface of javax.servlet

INTERFACES	CLASSES
Servlet	ServletInputStream
ServletContext	ServletOutputStream
ServletConfig	ServletRequestWrapper
ServletRequest	ServletResponseWrapper
ServletResponse	ServletRequestEvent
ServletContextListener	ServletContextEvent
RequestDispatcher	ServletRequestAttributeEvent
SingleThreadModel	ServletContextAttributeEvent
Filter	ServletException
FilterConfig	UnavailableException
FilterChain	GenericServlet
ServletRequestListener

  Some Important Classes And Interface of javax.servlet

CLASSES and INTERFACES
HttpServlet	HttpServletRequest
HttpServletResponse	HttpSessionAttributeListener
HttpSession	HttpSessionListener
Cookie	HttpSessionEvent