code: public static void loadCascadedPropertiesFromResources(String configName) throws IOException {
          Properties props = loadCascadedProperties(configName);
          if (instance instanceof AggregatedConfiguration) {
              ConcurrentMapConfiguration config = new ConcurrentMapConfiguration();
              config.loadProperties(props);
              ((AggregatedConfiguration) instance).addConfiguration(config, configName);
          } else {
              ConfigurationUtils.loadProperties(props, instance);
          }
      }
docs: Load resource configName.properties first. Then load configName-deploymentEnvironment.properties
  into the system wide configuration. For example, if configName is "application", and deployment environment
  is "test", this API will first load "application.properties", then load "application-test.properties" to
  override any property that also exist in "application.properties".
  
  @param configName prefix of the properties file name.
  @throws IOException
  @see DeploymentContext#getDeploymentEnvironment()