code: @Override
  	public void putAll(final Map<? extends Object, ? extends Object> t) {
  		lock.writeLock().lock();
  		try {
  			properties.putAll(t);
  		} finally {
  			lock.writeLock().unlock();
  		}
  	}
docs: /*
  (non-Javadoc)
  
  @see java.util.Hashtable#putAll(java.util.Map)