Overloaded methods are methods with the same name signature but either a different number of parameters or different types in the parameter list. For example 'spinning' a number may mean increase it, 'spinning' an image may mean rotate it by 90 degrees. By defining a method for handling each type of parameter you achieve the effect that you want.
Overridden methods are methods that are redefined within an inherited or subclass. They have the same signature and the subclass definition is used.
Polymorphism is the capability of an action or method to do different things based on the object that it is acting upon. This is the third basic principle of object oriented programming. Overloading and overriding are two types of polymorphism. Now we will look at the third type: dynamic method binding.
Assume that three subclasses (Cow, Dog and Snake) have been created based on the Animal abstract class, each having their own speak() method.

public class AnimalReference
{
  public static void main(String args[])
  Animal ref                 // set up var for an Animal
  Cow aCow = new Cow("Bossy"); // makes specific objects
  Dog aDog = new Dog("Rover");
  Snake aSnake = new Snake("Ernie");

  // now reference each as an Animal
  ref = aCow; ref.speak();
  ref = aDog; ref.speak();
  ref = aSnake; ref.speak();
}
Notice that although each method reference was to an Animal (but no animal objects exist), the program is able to resolve the correct method related to the subclass object at runtime. This is known as dynamic (or late) method binding.