Methods for consideration:
Overhaul Validate class
I have a problem with this one : I've done the isInstance and isAssignable, but I don't know which exception to throw...I was thinking about IllegalClassException, but it seems to have disappeared from LANG, so I think there's a good reason...Any help ?
Go with IllegalArgumentException. It was the parent class of IllegalClassException.
Attached patch with tests
Patch looks good. Does this match your thoughts Paul?
Should it be isAssignableFrom instead of isAssignable?
Patch applied with change of name to isAssignableFrom.