code: @Nonnull
    public static String getContextPath ()
    {
      String ret = s_sCustomContextPath;
      if (ret == null)
        ret = s_sServletContextPath;
      if (ret == null)
        throw new IllegalStateException ("No servlet context path present!");
      return ret;
    }
docs: Returns the context path of the web application.
  <p>
  The context path is the portion of the request URI that is used to select the
  context of the request. The context path always comes first in a request URI.
  The path starts with a "/" character but does not end with a "/" character.
  For servlets in the default (root) context, this method returns "".
  <p>
  It is possible that a servlet container may match a context by more than one
  context path. In such cases the context path will return the actual context
  path used by the request and it may differ from the path returned by this
  method. The context path returned by this method should be considered as the
  prime or preferred context path of the application.
  
  @return The context path of the web application, or "" for the default (root)
  context