Null field not persisted for Dates

[Jerry Carter]

Using OpenJPA 2.0.1, I have a date field in my entity.  Setting the field to a 
non-null value causes the data to be persisted as one would expect.  Setting 
the value to null, however, does not trigger an UPDATE operation.  I'm still 
digging, but I'm sure that someone else has encountered this.

FWIW, the annotations for the field are simple:

@Temporal(TemporalType.DATE)
@Column(name="purchase_date" private Date purchaseDate;

I do not specify 'nullable', but it defaults to true and the field supports a 
NULL value in the database.

-=- Jerry