Have you tried char[] or Character[]? If you can change your underlying database, it would probably be easier to to just use varchar2(2) mapped to a string. You can use Hibernate validators to ensure the length is 2 and it is not null. You can also use a check constraint in the database itself if you want to ensure the length and not null. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4093550#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...