code: public static ApplicationProperties configure(Application app,
  			ApplicationProperties config) {
  		if (properties != null) {
  			throw new ApplicationConfigurationException(
  					"re-configure ApplicationProperties not allowed.");
  		}
  		properties = config;
  		return properties;
  	}
docs: Set up {@link ApplicationProperties}.
  
  @param app
  {@link Application}
  @param config
  {@link ApplicationProperties}
  @return {@link ApplicationProperties}