Trying to create an equals method

Question

So I need to create an equals method within a class that and object can call with a second object to test equivalence. I mean whether or not the object's instance variable are all the same. Here's the snippets of code:
public class Circle implements Shape
    double radius;
    Point position;
    Color color;
    boolean filled;
public boolean equals(Object o)
        if(!(o instanceof Point)) {
            return false;
        Point p = (Point) o;
        return ((radius == p.radius) && (position == p.position) && (color == p.color) && (filled == p.filled));
}Obviously there's other methods going on in between the instance variables, but the constructor only sets the instance variables, nothing more. So the first error I'm getting is "cannot find symbol - variable radius", but clearly, it's there. What am I doing wrong?
I may have other questions when I get frther in my project.

Answer 1

sublimeph03nix wrote:
public boolean equals(Object o)
if(!(o instanceof Point)) {
return false;
}Not actually always desirable, that. Yes, yes, yes, it prevents a ClassCastException, but on the downside, it prevents a ClassCastException. What do I mean? Well, in situations where you know that nothing other than a Point object should be passed into this method - that's your intended behaviour - the presence of anything else here indicates a bug. Better to let the bug bring the app down than for it to continue doing the wrong thing. Testing will expose the bug, as long as you don't just ignore it.
Of course, this isn't always the case. It's one of those things you should consider on a case-by-case basis, rather than apply one idiom or the other all the time