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

6.6 - Wildcards in Generics

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Learning

Practice Questions

Test your understanding with targeted questions

Question 1 Easy

What is an unbounded wildcard?

💡 Hint: Think about generic lists.

Question 2 Easy

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

💡 Hint: Consider how to indicate no type restriction.

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

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

💡 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

💡 Hint: Reflect on the generalization vs. specialization.

1 more question available

Challenge Problems

Push your limits with advanced challenges

Challenge 1 Hard

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

💡 Hint: Consider type-checking when counting objects.

Challenge 2 Hard

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

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

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Reference links

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