Runtime DB mapping to class/objects?

Say someone requests the possibility of mapping DB tables to instances in a user interface开发者_JAVA百科. How could this be handled and what form could the domain take?

Example requested by David:

DB

Person

• FirstName
• LastName
• Age
• ...

In Java GUI

• Entity Identifier: Person
• Source table: Person
• Attribute identifier: firstName
• Source column: FirstName
• ...

[Accept button] => activate mapping/create instances

P.S: Doing things this way is probably more trouble than it's worth. I'm open to ideas.