Appengine Cloud Endpoints：获取模型对象方法的NPE

I'm using Cloud Endpoints to retrieve data from appengine to android. Using the generated library I retrieve a list of objects. This appears to work fine, and if I log the object I see the json. However if I use a getX() on the object I get a NPE. Java GAE 1.8.7. Doing this in an AsycTask in activity.I'm using Cloud Endpoints to retrieve data from