TheconfusionaboutjspfourscopesandServletContext,HttpSession,HttpServletReqest,PageContext

      The jsp four scopes are same with ServletContext,HttpSession,HttpServletRequest,PageContext?
   
       How servlet is initialized by servlet container,is also order?
        
       In a jsp or servlet,getSession method  what can get, and how could put variable into scope(How do declare scope for variable?)?