title: how to generate unique id in google app engine for java
body: <p>am trying to store a list of files dynamically in google app engine. I can view the list of files in the data store viewer with the name and default id/name in it (Say id/name=4002), if i want to retieve this id (id/name=4002) is there any function provided for this by google?. Also can i use some unique id generators manually adding inside the viewer?. Suggest me an idea.  </p>