There is obsolete link to Spring's PetClinic example (http://static.springsource.org/docs/petclinic.html), should be https://github.com/spring-projects/spring-petclinic.

Also the sentence "A simple comment change in `web.xml` switches between the data access strategies." is wrong. The profiles are now defined in `business-config.xml` and to swithch the profie you have to rewrite the `<param-name>spring.profiles.active</param-name>` parameter. So this should be reworded a bit.