docs: public List<ModelServiceInstance> queryService(List<StringCommand> commands){
  
          ProtocolHeader header = new ProtocolHeader();
          header.setType(ProtocolType.QueryService);
  
          List<QueryCommand> cs = new ArrayList<QueryCommand>();
          for(StringCommand c : commands){
              cs.add(c.getStringCommand());
          }
  
          QueryServiceProtocol p = new QueryServiceProtocol(cs);
          QueryServiceResponse resp ;
          resp = (QueryServiceResponse) connection.submitRequest(header, p,  null);
          return resp.getInstances();
      }