AP CSA Unit 4 Day 11: Arraylist Add With Index

February 6, 2026

Unit 4, Data Collections • Cycle 2

Day 11 Advanced Practice • Harder Difficulty

Focus: ArrayList Add with Index Hard ArrayList Add with Index

Advanced Practice Question

Format: ArrayList Add with Index

What is the output?

ArrayList list = new ArrayList<>();
list.add(10);
list.add(20);
list.add(30);

list.add(1, 15);

System.out.println(list);

Difficulty: Hard | Topic: ArrayList Add with Index | Cycle: 2 (Advanced)

Why This Answer?

add(1, 15) inserts 15 at index 1, shifting 20 and 30 to the right. Result: [10, 15, 20, 30].

Common Mistake

Watch Out!

Thinking add(index, value) replaces instead of inserts.

AP Exam Strategy

add(index, value) = insert at index, shifting others right. set(index, value) = replace.

This Cycle 2 HARD question tests arraylist add with index. Review Unit 4 concepts to build mastery of data collections.

Cycle 2 questions prepare you for the hardest AP CSA exam questions.