code: public static void registerHandler (ResourceManager rmgr)
      {
          // we only want to wire up our Handler once, but if a new resource
          // manager comes along, we'll point the existing handler there
          if (_rmgr == null) {
              // wire up our handler with the handy dandy attachable URL factory
              AttachableURLFactory.attachHandler("resource", Handler.class);
          }
          _rmgr = rmgr;
      }
docs: Register this class to handle "resource" urls ("resource://<i>resourceSet</i>/<i>path</i>")
  with the specified ResourceManager.