Querying by non-mongo-generated Id (Java UUID) in Morphia
===

I know this is fairly embarrassing because querying by ID is like a trivial use case of databases, but for some reason, I'm having issues with the java UUID class. 

     public class ARecord extends Observable implements Cloneable, Record {
	    @Id private UUID uuid;
        @Indexed private String text;
	    public ARecord(String text){
            this.text = text; 
            this.uuid = UUID.nameUUIDFromBytes(text.getBytes()); }

Assume for the sake of brevity that the messages are unique (ie valid as an Id field when turned into UUIDs). Now why does this: 
     
     public void upA(UUID uuid){
      ARecord ar = ds.get(ARecord.class,uuid);
      System.out.println(ar.toString());

and this: 
    
    public void upB(UUID uuid){
    Query q = ds.createQuery(ARecord.class).filter("_id", uuid);
    System.out.println(q.asList().get(0).toString());

throw a NPE?

If I change the `@Id` field to `private double uuid` it works fine. So.... what about the java UUID class am I doing wrong? Later on in a different piece of code I'm trying to call `ARecord r = up(UUID.nameUUIDFromBytes(text.getBytes());` which implies that the uuid should be the right uuid that i'm querying...

Any ideas?
