May I need avoid composition without annotations with Hibernate and MySQL?

Question

In my project which is based on Hibernate and MySQL I'm using barcode so I have set primary key to bracode as well as id field and since there's composition it's problematic that occurring :

org.hibernate.id.IdentifierGenerationException: null id generated for:class com.pojo.MyClass

So I'm not using @annotations
I've checked without composition and just make barcode unique rather set primary key so would this approach could be cause of any future problem in my project?

Answer 1

If the barcode for you entity is unique identifier just put @Id annotation on this field and put the unique constrain in the data base for that field as well. If you are using several fields as unique constrain in this case you should use composite key. If I get you question right.