Quick Answer
The answer is [A, C, B] because the `add(int index, E element)` method inserts the element at the specified index, shifting all subsequent elements to the right. When you call `list.add(1, "C")` on a list initially containing [A, B], the element "C" is placed at index 1, which moves "B" to index 2, producing the final order [A, C, B]. This question tests your understanding of the `ArrayList` insertion behavior, a common topic on the Oracle Certified Professional Java SE 17 Developer 1Z0-829 exam, where the trap is confusing this method with `set()`, which replaces an element instead of inserting. A frequent mistake is assuming `add(1, "C")` overwrites the element at index 1, but it always shifts existing elements right without removing any. Remember the mnemonic: "Add shifts right, set overwrites tight."
This 1Z0-829 practice question tests your understanding of working with arrays and collections. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer writes: List<String> list = new ArrayList<>(); list.add("A"); list.add("B"); list.add(1, "C"); System.out.println(list); What is the output?
[A, C, B]
Correct insertion order.
[A, B, C]
Why wrong: Incorrect; C is inserted at index 1.
[A, B]
Why wrong: Incorrect; element C is added.
[C, A, B]
Why wrong: Incorrect; C is not at index 0.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
[A, C, B]
The correct answer is A because the `add(int index, E element)` method inserts the element at the specified index, shifting subsequent elements to the right. Initially, the list is [A, B]. After `list.add(1, "C")`, "C" is inserted at index 1, moving "B" to index 2, resulting in [A, C, B].
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
[A, C, B]
Why this is correct
Correct insertion order.
Related concept
Read the scenario before looking for a memorised answer.
[A, B, C]
Why it's wrong here
Incorrect; C is inserted at index 1.
[A, B]
Why it's wrong here
Incorrect; element C is added.
[C, A, B]
Why it's wrong here
Incorrect; C is not at index 0.
Common exam traps
The trap here is that candidates often confuse the `add(E element)` method (which appends at the end) with the `add(int index, E element)` method (which inserts at a specific index), leading them to mistakenly think "C" is appended or placed at the beginning.
Detailed technical explanation
The `ArrayList.add(int index, E element)` operation has O(n) time complexity because it shifts all elements from the specified index onward to the right by one position. This is implemented by calling `System.arraycopy()` internally to move the underlying array elements. In real-world scenarios, frequent insertions at arbitrary positions can degrade performance, making `LinkedList` a better choice for such patterns.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the 1Z0-829 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
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FAQ
Working with Arrays and Collections — This question tests Working with Arrays and Collections — Read the scenario before looking for a memorised answer..
The correct answer is: [A, C, B] — The correct answer is A because the `add(int index, E element)` method inserts the element at the specified index, shifting subsequent elements to the right. Initially, the list is [A, B]. After `list.add(1, "C")`, "C" is inserted at index 1, moving "B" to index 2, resulting in [A, C, B].
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Same concept, more angles
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Given ArrayList<Integer> numbers = new ArrayList<>(List.of(1,2,3,4)); Which statement will insert element 10 at index 2?
easyWhy B: Option B is correct because the `ArrayList.add(int index, E element)` method inserts the specified element at the given index, shifting existing elements to the right. Here, `numbers.add(2,10)` inserts 10 at index 2, resulting in the list [1,2,10,3,4].
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Last reviewed: Jun 11, 2026
This 1Z0-829 practice question is part of Courseiva's free Oracle certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 1Z0-829 exam.
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