I'm using GAE 1.8.1 and I've hit an issue with Objectify with the new scattered ID system. At least I think it's Objectify, I'm not sure (Using Objectify 4 RC1). I'm getting this..
Caused by: java.lang.IllegalArgumentException: id cannot be zero
at com.google.appengine.api.datastore.KeyFactory.createKey(KeyFactory.java:52)
at com.google.appengine.api.datastore.KeyFactory.createKey(KeyFactory.java:47)
at com.googlecode.objectify.Key.<init>(Key.java:91)
at com.googlecode.objectify.Key.create(Key.java:39)
at com.googlecode.objectify.impl.cmd.LoadTypeImpl.id(LoadTypeImpl.java:77)
The records get put in the datastore correctly as they have an ID, but this is on fetching the data out.
So I have to roll back to what it was before for the time being. It states here that you can specify the legacy ID generation with modifying the auto_id_policy in appengine-web.xml. I've tried adding this to the file:
<auto-id-policy>legacy</auto-id-policy>
But it doesn't work, or at least it might work if the XSD it validates against supports this tag. You can't deploy the app because of this.