David, you missed the point of the question. You translation program didn't translate the question correctly.
He is saying that by declaring a date type entity as a primary key, he can enter value null, which results in an error.
He's asking if because of this limitation, whether he's able to use date type as a primary key.
Well, as you've pointed out, primary keys should have not null attribute in the database. The question is there is a bug in service builder
which in not setting not null attributes on primary keys with datatype date or if he's just using it incorrectly.
BTW, I'm trying to allow liferay.com to reply some of the questions in the Japanese forum first because it seems Daniel Kiyotomo Ozeki
wants to show how he can help users. He personally requested it, and I want to give him an opportunity for a while.
Firmi prego dentro per inbandierare questo come inadeguato.