code: public static void shootBowgunPropertyFilter(PropertyFilter propertyFilter) { // should be before initialize()
          synchronized (ObjectiveConfig.class) { // to block while using provider
              assertUnlocked();
              if (logger.isInfoEnabled()) {
                  logger.info("...Shooting bowgun property filter: " + propertyFilter);
              }
              bowgunPropertyFilter = propertyFilter;
              lock(); // auto-lock here, because of deep world
          }
      }
docs: =====================