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Learn New Java Features – Module 4 Lesson 3- Quiz

Last updated: December 14, 2025

Written by: komal

Learn What’s New in Java
Lesson 3: Unnamed Variables and Patterns
Learn New Java Features – Module 4 Lesson 3- Quiz

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Question 1 of 5

1. Question

What is the primary purpose of using an unnamed variable?

To create global variables accessible anywhere.
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To improve performance by skipping garbage collection.
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To automatically initialize variables to null.
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To signal that a variable is syntactically required but intentionally unused in the logic.
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Question 2 of 5

2. Question

According to the lesson, which of the following is NOT a valid place to use an unnamed variable?

Inside a catch block (e.g., catch (Exception _))
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In a lambda expression (e.g., (_, value) -> …)
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As a regular method parameter in a class method definition
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In a try-with-resources block
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Question 3 of 5

3. Question

Consider the following code snippet regarding a lambda expression:

map.replaceAll((_, val) -> val.toUpperCase());

What does the _ represent here?

The map's key, which is being ignored.
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The map's value, which is being ignored.
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A syntax error, as lambdas cannot use _.
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A wildcard matching any type.
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Question 4 of 5

4. Question

How does the unnamed variable function within a try-with-resources block?

It prevents the resource from being closed automatically.
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It allows us to open a resource for its side effects without needing to reference the variable handle
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It keeps the resource open until the JVM shuts down.
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It disables the AutoCloseable interface.
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Question 5 of 5

5. Question

Why might a developer use var _ = queue.poll() instead of just queue.poll()?

To prevent the queue from throwing an exception.
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To store the result in a hidden system cache.
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To explicitly signal that the return value is being ignored, potentially avoiding static analysis warnings.
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To cast the result to a generic Object automatically.
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