code: public ExtServletContext getServletContext(HttpContext httpContext) {
          synchronized (this.contextMap) {
              ExtServletContext context = this.contextMap.get(httpContext);
              if (context == null) {
                  context = addServletContext(httpContext);
              }
  
              return context;
          }
      }
docs: Servlet objects require a ServletContext object. This object provides a number of functions to access
  the Http Service Java Servlet environment. It is created by the implementation of the Http Service for
  each unique HttpContext object with which a Servlet object is registered.
  <p>
  Thus, Servlet objects registered with the same HttpContext object must also share the same ServletContext object.
  
  @param httpContext
  @return