How to make Hibernate ignore a method?

Add @Transient to the method then Hibernate should ignore it.

To quote the Hibernate Documentation:

Every non static non transient property (field or method depending on the access type) of an entity is considered persistent, unless you annotate it as @Transient.

RNJ is correct, but I might add why this happens:

I'm guessing that you have annotated the getters of your persistent class. The prefixes used by java beans are "set" and "get", which are used do read and write to variables, but there is also the prefix "is", which is used for boolean values (instead of "get"). When Hibernate sees your getter-annotated persistent class, and finds a method "isVacant", it assumes that there is a property "vacant", and assumes that there is a "set"-method as well.

So, to fix it, you could either add the @Transient annotation, or you could change the name of your method to something that doesn't start with "is". I don't think this would be a problem if your class was annotated on the fields, instead of the get-methods.