Practice Wildcards in Generics - 6.6 | 6. Generics and Type Inference | Advance Programming In Java
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6.6 - Wildcards in Generics

Learning

Practice Questions

Test your understanding with targeted questions related to the topic.

Question 1

Easy

What is an unbounded wildcard?

πŸ’‘ Hint: Think about generic lists.

Question 2

Easy

Write a method that accepts any list using an unbounded wildcard.

πŸ’‘ Hint: Consider how to indicate no type restriction.

Practice 4 more questions and get performance evaluation

Interactive Quizzes

Engage in quick quizzes to reinforce what you've learned and check your comprehension.

Question 1

What is the purpose of an unbounded wildcard in Java?

  • To limit types to a specific class
  • To accept any type
  • To restrict types to a lower level

πŸ’‘ Hint: Consider the flexibility allowed without specific criteria.

Question 2

True or False: Lower bounded wildcards allow the specified type and its subclasses.

  • True
  • False

πŸ’‘ Hint: Reflect on the generalization vs. specialization.

Solve 1 more question and get performance evaluation

Challenge Problems

Push your limits with challenges.

Question 1

Write a generic method using an upper bounded wildcard that takes a list of Animals and returns the count of Dogs in it.

πŸ’‘ Hint: Consider type-checking when counting objects.

Question 2

Create a method to add objects of any superclass type to a list of Integer, including handling exceptions if added wrongly.

πŸ’‘ Hint: Think carefully about what type checks you need to ensure insertions are type-safe.

Challenge and get performance evaluation