Ways to Represent Oracle Object Types in Entity Objects

Because the database data types are in SQL and the business logic tier types are in Java, Business Components for Java needs to translate between the two:

Techniques for creating domains for Oracle Object Types

If you aren't going to have the wizard generate domains for you, you need to create them yourself. In general, you follow the steps in Representing an Oracle Object Type with a User-defined Domain.

Also, there are specific techniques for complex or nested objects:

Limitations on using Oracle Object Types with business components