Mastering Java: The Ultimate Quiz for 'Thinking in Java'

Which class will not throw a compilation error if extended by adding a new checked exception to a method signature?

1. A class that implements an interface

2. A final class

3. An abstract class

4. None, adding a new checked exception is always an error

The correct answer is: An abstract class

Classes that implement an interface (A) will also throw a compilation error due to the need for the method to be implemented. Final classes (B) cannot be extended, so adding a checked exception to their method signature would not be possible. Abstract classes (C) allow for flexibility in method signatures and do not throw compilation errors when a new checked exception is added. Option D states that none of the classes will throw a compilation error, which is incorrect as stated in the question.