final methods
Figure 480. Implementing 
Shape movements public class Shape {
/**
* Move by a given translation vector
* @param xTrans Translation's x component
* @param yTrans Translation's y component
*/
public void move(final int xTrans, final int yTrans) {
x += xTrans;
y += yTrans;
} ...Figure 481. Fools are everywhere!
public class Rectangle extends Shape {
@Override public void move(int xTrans, int yTrans) {
// I'm so dumb!
...
}Figure 482. Solution: final prevents
overriding
public abstract class Shape {
... public final void move(final int xTrans, final int yTrans) {
x += xTrans;
y += yTrans;
}...public class Rectangle extends Shape {
// Syntax error: 'move(int, int)' cannot override
// 'move(int, int)' in 'inherit.Shape'; overridden method is final
@Override public void move(int xTrans, int yTrans) {...