I don't agree - it's what I'd call a read-only-property...
Quite another question is, how hibernate should handle those read-only-properties...
See section 2.1.1 Persistent Fields and Properties of the spec, quoted below,
"It is required that the entity class follow the method signature conventions for JavaBeans read/write
(as defined by the JavaBeans Introspector class) for persistent properties when persistent properties are used.
In this case, for every persistent property property
of type T of the entity, there is a getter method, getProperty, and setter method setProperty. For boolean properties, isProperty is an alternative name for the getter method."
This also brings us to my other question,viewtopic.php?f=1&t=999049
Clearly, from the spec, isProperty is an alternative for getter. So presence of isX and getX should not result in MappingException.
IMO, both of these are hibernate bugs.