The sentence

"You can even mix the table per hierarchy and table per subclass strategies using the following approach: "

at http://www.redhat.com/docs/en-US/JBoss_Enterprise_Application_Platform/5.0.0/html-single/Hibernate_Core/index.html#inheritance-mixing-tableperclass-tablepersubclass

should be

"You can even mix the table per class hierarchy and table per subclass strategies using the following approach: "

note the extra word 'class'