Java 5 introduces covariant return types

With Java 5 this has changed: Java 5 permits covariant return types.
This means that Java 5 does not insist that the return type of an overriding method is the same type as the return type of the method in the superclass: it can be a subclass of that return type.
So, in Java 5, Circle's translate method can have the header:
```
0367:    public Circle translate(int pX, int pY)
```

And the call of this method can then be simplified to:

0406:                Circle tCircle = new Circle(x, y, radius);
0407:                Circle tNewCircle = tCircle.translate(1, 2);
0408:                System.out.println(tNewCircle.getRadius());