final Methods & Classes

• We have seen that variables can be declared final, indicating that they cannot be modified.
• Analogously, methods and classes can be declared final.
• When the final modifier is applied to a method, it cannot be overridden by subclasses.

  This allows the Java compiler to produce more efficient runtime code; no runtime checks need be made regarding which method to invoke.

• When a final modifier is applied to a class, it cannot be subclassed.

  All methods of a final class are implicitly final (and thus subject to some compiler optimizations).