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

What is a disadvantage of not using a null object when a method returns null?

1. The necessity of using complex exception handling

2. Forcing clients to implement their own null handling

3. Breaking the application's compile-time type safety

4. Requiring manual garbage collection for null references

The correct answer is: Forcing clients to implement their own null handling

Not using a null object when a method returns null forces clients to implement their own null handling, which can be time-consuming and error-prone. This can lead to potential bugs and inconsistencies in the code. Additionally, it goes against the concept of encapsulation, as clients should not have to worry about the internal workings of a method and how it handles null values. Options A, C, and D are also incorrect as they do not directly address the issue of not using a null object. Option A only applies if the method throws a checked exception when it returns null, which is not always the case. Option C is unrelated to null objects and option D refers to memory management, which is not affected by the use of null objects.