AP CSA ArrayList - Traps, FRQ Patterns & Practice Questions (2026)

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FRQ 3 — Always ArrayList

AP CSA ArrayList — Complete Exam Guide

FRQ 3 is worth 9 points and it is always ArrayList. Master the traps, patterns, and methods that graders check for.

FRQ 3Always ArrayList
9 ptsFRQ 3 Value
May 15Exam Date 2026
AP CSA Exam: May 15, 2026. FRQ 3 is always ArrayList. These traps cost students 2–4 points every year.

Traps & Common Mistakes

ConcurrentModificationException, index shifting, autoboxing — fix these before exam day.

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ArrayList Traps Every AP CSA Student Falls For

6 traps: ConcurrentModificationException, index shifting, remove(int) vs remove(Object), and more.

LiveExam Critical

Trace & Predict Output

Track every add, remove, and set call. The shifting indices are where students lose points.

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ArrayList Trace Problems — Predict the Output

5 trace problems with add, remove, set sequences. Track the index shifts step by step.

LiveExam Critical

FRQ 3 Patterns & Scoring

Know exactly how to earn every point on FRQ 3.

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ArrayList FRQ Patterns — What Graders Look For

Constructor patterns, filter/remove, build pairs. Scoring checklists and penalty triggers.

LiveExam Critical

Master FRQ 3 Before May 15

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Comparisons & Reference

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Array vs ArrayList: What the Exam Tests

Side-by-side syntax, methods, exam traps. The differences College Board targets.

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Array & ArrayList Methods Quick Reference

Every method and syntax pattern for both data structures.

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Interactive Practice

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Write Real Code — FRQ-Style Practice With Auto-Grader

8 interactive problems. Write Java, run it, get instant feedback.

LiveInteractive

Explore Other Unit 4 Topics

Arrays Hub →

Mistakes, searching, sorting, trace problems.

2D Arrays Hub →

FRQ 4 patterns, nested loops, traversal.

Unit 4 Overview →

Full Unit 4 Data Collections super-hub.

Practice Questions Hub →

All interactive practice by topic.

FRQ Archive →

All FRQs 2004–2025 with solutions.

Unit 4 Study Guide →

Complete study guide for all Unit 4 topics.

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