Spring Data JPA: Default lock mode?

What is the default lock mode when using Spring Data JPA?

With respect to Spring Data JPA's 1.3.0.RELEASE locking documentation:

1. What is the default lock mode of org.springframework.data.jpa.repository.JpaReposit ory<T, ID>'s methods?
2. What is the default lock mode of any additionally declared method (e.g. findByX(...)) if no @org.springframework.data.jpa.repository.Lock annotation is provided?

With respect to a more general question over at StackOverflow, if no further annotation is specified, will the default lock mode be determined by what my "database stack" is configured to?

My database stack is:

Spring Data JPA repositories (1.3.0.RELEASE)
JPA entities (JPA 2.0)
Hibernate (4.1.7.Final)
C3P0 (connection pool) (0.9.1.2)
MySQL Server InnoDB (5.5)