What is the result of the following code? List list = List.of("A", "B"); list.add("C"); System.out.println(list);

Working with Arrays and Collections →easyMultiple ChoiceObjective-mapped

1Z0-829 Working with Arrays and Collections Practice Question

What is the result of the following code? List<String> list = List.of("A", "B"); list.add("C"); System.out.println(list);

⚠ Common exam trap

Candidates often assume `List.of()` returns a regular mutable `ArrayList` or that the code will simply ignore the `add` call, but the exam tests the specific runtime exception behavior of immutable collections created by factory methods.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

An exception is thrown at runtime

The `List.of()` factory method returns an immutable list. Calling `add()` on an immutable list throws an `UnsupportedOperationException` at runtime, so the code does not compile or run successfully. Option C is correct because the exception is thrown when the `add` method is invoked.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
[A, B, C]
Why it's wrong here
List.of returns immutable list, add not allowed.
✗
[A, B]
Why it's wrong here
Exception is thrown, not printed.
✓
An exception is thrown at runtime
Why this is correct
UnsupportedOperationException thrown.
✗
Compilation error
Why it's wrong here
list.add is a valid method call, compiles.

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1Z0-829 Working with Arrays and Collections Practice Question

Why each option matters

Option-by-option breakdown

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