What is the danger to calling Validation.buildDefaultValidator()? Should I be sharing this resource, or is that taken care for me behind the scenes?

I really don't want to be passing references to a validator deep down in objects... so what is the best practice here? Treat it like a dao or datasource? Or treat it like a pojo?

Building might be expensive in terms of performance, and the validators are designed to be reused.
You should use it as a service, how you use services depends on your environment. (?)

That's why it's especially useful when integrated in frameworks, like Seam uses Hibernate Validator (v3)
to validate web forms mapped to pojos and Hibernate validates objects before persisting them, or after loading
from DB.

I would grab it from Spring, but there are only 2 ways to do this within spring.

1. Use AOP to @Autowire the pojo whenever it's instantiated (because it is not part of the layering or a factory method)
2. Use a static method to get the spring application context in order to get the bean. I don't know how safe/dangerous this is.

Thoughts?