code: public static ApplicationDefinition getAppDef(RESTClient restClient, String appName)  {
          
          // GET /_applications/{application}
          Utils.require(!restClient.isClosed(), "Client has been closed");
          Utils.require(appName != null && appName.length() > 0, "appName");
  
          try {           
              StringBuilder uri = new StringBuilder(Utils.isEmpty(restClient.getApiPrefix()) ? "" : "/" + restClient.getApiPrefix());                     
              uri.append("/_applications/");
              uri.append(Utils.urlEncode(appName));
              RESTResponse response = restClient.sendRequest(HttpMethod.GET, uri.toString());
              logger.debug("listApplication() response: {}", response.toString());
              if (response.getCode() == HttpCode.NOT_FOUND) {
                  return null;
              }
              ApplicationDefinition appDef = new ApplicationDefinition();
              appDef.parse(getUNodeResult(response));
              return appDef;
          } catch (Exception e) {
              throw new RuntimeException(e);
          }
      }
docs: Get the {@link ApplicationDefinition} for the given application name. If the
  connected Doradus server has no such application defined, null is returned.
  
  @param appName   Application name.
  @return          Application's {@link ApplicationDefinition}, if it exists,
  otherwise null.