code: @Nonnull
    public static String getURIWithContext (@Nonnull final String sHRef)
    {
      ValueEnforcer.notNull (sHRef, "HRef");
  
      // If known protocol, keep it
      if (hasKnownProtocol (sHRef))
        return sHRef;
  
      final String sContextPath = ServletContextPathHolder.getContextPath ();
      return _getURIWithContext (sContextPath, sHRef);
    }
docs: Prefix the passed href with the relative context path in case the passed
  href has no protocol yet.<br>
  Important: this method does not add the session ID in case cookies are
  disabled by the client!
  
  @param sHRef
  The href to be extended. May not be <code>null</code>.
  @return Either the original href if already absolute or
  <code>/webapp-context/<i>href</i></code> otherwise. Never
  <code>null</code>.