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Question 359 of 513
Working with Arrays and CollectionsmediumMultiple ChoiceObjective-mapped

1Z0-829 Working with Arrays and Collections Practice Question

Consider: List<Integer> list = new LinkedList<>(); list.add(10); list.add(20); list.add(0,5); System.out.println(list); What is the output?

⚠ Common exam trap

Watch out — candidates often confuse the `add(index, element)` method with `set(index, element)`, or incorrectly assume that adding at index 0 replaces the first element rather than inserting before it.

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

[5,10,20]

The code creates a LinkedList and adds 10, then 20. The third call `list.add(0,5)` inserts 5 at index 0, shifting existing elements to the right. The resulting list is [5,10,20], so option B is correct.

Answer analysis

Option-by-option breakdown

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

  • [10,5,20]

    Why it's wrong here

    This would occur if add(1,5) were called, not add(0,5).

  • [5,10,20]

    Why this is correct

    add(0,5) inserts at the beginning.

  • [10,20,5]

    Why it's wrong here

    This would happen if the element were appended, not inserted at index 0.

  • [5,10,20] but with type warning

    Why it's wrong here

    No type warning as generics are used correctly.

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Last reviewed: Jun 25, 2026

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