@XmlElement(nillable=true) annotation on type properties causes json serialization to include null values

[raphj]

type properties are annotated with @XmlElement(nillable=true).

This causes "type":null to be output in the json seralization of the corresponding objects in user resources (for Email, Entitlement, Role, Im, Photo, X509Certificate).

I tried with @XmlElement, removing (nillable=true), and this seems to produce the expected results and doesn't seem to cause issues on a quick test.

Is nillable=true necessary, or can we remove it?