EJB3.1 spec, section 4.8.5.5 has specific rules for @Lock annotation on super class(es) of bean:

If the bean class has superclasses, the following additional rules apply:

• A concurrency locking attribute specified on a superclass S appplies to the business methods defined by S. If a class-level concurrency attribute is not specified on S, it is equivalent to specification of Lock(WRITE)on S.

• A concurrency locking attribute may be specified on a business method M defined by class S to override for method M the concurrency locking attribute value explicitly or implicitly specified on the class S.

• If a method M of class S overrides a business method defined by a superclass of S, the concurrency locking attribute of M is determined by the above rules as applied to class S.

These rules need to be taken into account while creating metadata as well as at runtime, during bean invocation.