Polymorphism vs Overriding vs Overloading

Question

In terms of Java, when someone asks:

what is polymorphism?

Would overloading or overriding be

Answer 1

Both overriding and overloading are used to achieve polymorphism.

You could have a method in a class that is overridden in one or more subclasses. The method does different things depending on which class was used to instantiate an object.

    abstract class Beverage {
       boolean isAcceptableTemperature();
    }

    class Coffee extends Beverage {
       boolean isAcceptableTemperature() { 
           return temperature > 70;
       }
    }

    class Wine extends Beverage {
       boolean isAcceptableTemperature() { 
           return temperature < 10;
       }
    }

You could also have a method that is overloaded with two or more sets of arguments. The method does different things based on the type(s) of argument(s) passed.

    class Server {
        public void pour (Coffee liquid) {
            new Cup().fillToTopWith(liquid);
        }

        public void pour (Wine liquid) {
            new WineGlass().fillHalfwayWith(liquid);
        }

        public void pour (Lemonade liquid, boolean ice) {
            Glass glass = new Glass();
            if (ice) {
                glass.fillToTopWith(new Ice());
            }
            glass.fillToTopWith(liquid);
        }
    }