Entity Beans with no primary keys. Is it possible to create an Entity Bean(CMP) based on table that does not have a primary key.

Yes, you can create CMP Entity Beans without primary keys. But you must be aware of the implications:

1. Duplicate records may be entered in the table
2. The findByPrimaryKey() method may return varying rows

In essence, CMP was not designed to not have primary keys, although it can work. The development process is the same as when you create CMP which has primary keys.