code: public void updateField(int appId, int fieldId,
  			ApplicationFieldConfiguration configuration) {
  		getResourceFactory()
  				.getApiResource("/app/" + appId + "/field/" + fieldId)
  				.entity(configuration, MediaType.APPLICATION_JSON_TYPE).put();
  	}
docs: Updates the configuration of an app field. The type of the field cannot
  be updated, only the configuration.
  
  @param appId
  The id of the app the field is one
  @param fieldId
  The id of the field to be updated
  @param configuration
  The new configuration of the field