code: public synchronized void save() throws IOException {
          if(BulkChange.contains(this))   return;
  
          if (initLevel == InitMilestone.COMPLETED) {
              LOGGER.log(FINE, "setting version {0} to {1}", new Object[] {version, VERSION});
              version = VERSION;
          } else {
              LOGGER.log(FINE, "refusing to set version {0} to {1} during {2}", new Object[] {version, VERSION, initLevel});
          }
  
          getConfigFile().write(this);
          SaveableListener.fireOnChange(this, getConfigFile());
      }
docs: Save the settings to a file.