I am using the @UnwrapValidatedValue with a custom Guava OptionalUnwrapper and sometimes OptionalUnwrapper#getValidatedValueType() is called also for non-Optional<> fields.

The bug reproduction is sporadic and tricky.

If you say sporadic, does it mean validating one and the same POJ sometimes shows the issue and in some other cases it doesn't, withou altering any parts of the code?

I managed to pinpoint it to ValidatorImpl#setValidatedValueHandlerToValueContextIfPresent() that does not perform valueContext.setValidatedValueHandler( null ) when there is no need for an unwrapper. Since valueContext is re-used between fields, it is possible for the OptionalUnwrapper to be first called for Optional fields and then re-used for non-Optional fields with the same validatedValueHandler of the Optional field.

Interesting, this doesn't seem correct indeed. Without having a closer loo I'd say the un-wrapper should be reset on the context between validation of different properties.

Mailing list discussion:
https://www.mail-archive.com/hibernate-dev@lists.jboss.org/msg11303.html

Attached is the test reproduction (requires Guava)