code: public void clear() {
  		domainsFileLock.writeLock().lock();
  		logger.trace("LOCK writelock");
  		allDomains = null;
  		domainMap = null;
  		logger.trace("UNLOCK writelock");
  		domainsFileLock.writeLock().unlock();
  	}
docs: Clears all domains, requiring the file to be reparsed for subsequent accesses