Hi NG!

I've just browsed the Hibernate-FAQ on www.hibernate.org a bit:

In the section "Common Problems" there are two questions:

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Q1:
I get org.hibernate.HibernateException: CGLIB Enhancement failed: <classname>?

A1:
If you use lazy loading with proxies (default for all classes in Hibernate 3), Hibernate needs to subclass your class at runtime. It can't do this if you have a private no-argument constructor. As per documentation, at least package visibility is required.

A bit further is another question:

Q2:
Hibernate is nontransparent because it requires me to have a default constructor which breaks the API of my class!

A2:
You may declare the constructor private. (Same goes for any property accessors.)


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So, what is the truth? May I or may I not declare my default constructor private?

Berti

As far as I know there should be a default constructor. What do you care having one anyway?

You can declare a private constructor but this will prevent hibernate creating a proxy for your class which might affect performance. Such a class must be marked as lazy="false" in the mapping file to indicate a proxy should NOT be created for the class - otherwise the error in Q1 may occur.

Ah, that explains the seeming opposite answers. Thank you!