code: @Nonnull
    @OverrideOnDemand
    protected SimpleURL getURLForNonExistingItem (@Nonnull final IRequestWebScopeWithoutResponse aRequestScope,
                                                  @Nonnull final String sKey)
    {
      return new SimpleURL (aRequestScope.getFullContextPath ());
    }
docs: Get the URL to redirect in case an invalid go mapping key was provided.
  
  @param aRequestScope
  The current request scope.
  @param sKey
  The key that was searched.
  @return Never <code>null</code>.