code: public synchronized XAttribute put(String key, XAttribute value) {
  		try {
  			XAttributeMap map = deserialize();
  			map.put(key, value);
  			serialize(map);
  			return value;
  		} catch (IOException e) {
  			e.printStackTrace();
  			return null;
  		}
  	}
docs: /* (non-Javadoc)
  @see java.util.Map#put(java.lang.Object, java.lang.Object)