code: public void setDefaultPrefix(final String prefix) {
  		lock.writeLock().lock();
  		try {
  			final String myPrefix = checkAndConvertPrefix(prefix);
  			final List<String> prefixList = split(myPrefix);
  			setDefaultPrefixes(prefixList);
  		} finally {
  			lock.writeLock().unlock();
  		}
  	}
docs: Sets the default prefix.
  
  @param prefix
  the new default prefix