Practice Generics And Wildcards In Collections (4.5) - Java Collections Framework (Advanced

Practice: Generics and Wildcards in Collections

Lesson 4.5Java Collections Framework (Advanced

Practise this section

8 questions

Flashcard drill
2 cards from this section. Quick, good the night before a test.
Exercise
6 questions · about 4 min · pass mark 70%. Hints available.
Sign up to start the exercise
Quiz
2 questions · about 1 min · pass mark 70%. Hints available.
Sign up to start the quiz

6 sample questions

Question 1.
What does a bounded wildcard in Java signify?
Show hintHide hint
Think about the terms 'extends' and 'super'.
Question 2.
Explain how type erasure impacts generics in Java.
Show hintHide hint
Consider what happens during the compilation of generic code.
3Question 3.
What does the wildcard List<? extends Number> indicate?
- It allows any Number type
- It only allows Integer type
- It restricts to superclasses of Number
Show hintHide hint
Think about the meaning of 'extends'.
4Question 4.
True or False: Type erasure keeps all type parameters intact in compiled Java code.
- True
- False
Show hintHide hint
Consider what happens in older Java versions.
Question 5.
Explain a scenario where using bounded wildcards can prevent potential runtime errors. Provide code samples for clarity.
Show hintHide hint
Consider data integrity in statistical applications.
Question 6.
Develop a method utilizing lower bounded wildcards that allows adding different shapes to a list. Explain the significance of this approach.
Show hintHide hint
Think about object-oriented programming and polymorphism.

4 more questions in this section. Enroll free to practise them all.