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

How do wildcards with upper bounds compare to those with lower bounds?

1. Upper bounds are more restrictive in adding objects

2. Lower bounds allow for any subtype of the specified class

3. Upper bounds permit more flexibility in method parameters

4. Lower bounds are suited for methods that need to consume objects of a certain supertype

The correct answer is: Lower bounds are suited for methods that need to consume objects of a certain supertype

Option B is incorrect because it is referring to a wildcard with an upper bound as opposed to lower bound. Wildcards with lower bounds restrict the type of objects that can be added to a collection, while upper bounds restrict the type of objects that can be consumed by a method. Option A is incorrect because it is describing the opposite behavior of upper bounds. Finally, option C is also incorrect because it is referring to a different type of wildcard, the unbounded wildcard, rather than an upper bound. Ultimately, option D is the correct answer because lower bounds are suited for methods that need to consume objects of a certain supertype, providing more flexibility in how the method can be used.