I've got a class called "channel". I've written two subclasses for it, both of which implement the "poll" method, however "channel" itself does not. When I run this, I get an error indicating poll() does not exist.

Code:

for (int j = 0; j < channels.size(); j++) {
 Channel the_channel = (Channel) channels.get(j);
 output.print(str(the_channel.poll()));
}
 

If I cast the_channel to one of the subclass types it will work (so long as the array contains only those types), and I suppose I could add an if statement to check what it's an instance of, but this seems to defeat the point of polymorphism. What am I missing?

You could also make Channel an interface, and then implement it with each of the subclasses.