Be Prepared - for the Computer Science Exam in Java - Chapter 5: Annotated Solutions to Past Free-Response Questions - 2026

Sep 22, 2026

Uploaded by Jacob

Chapter 5 compiles annotated solutions to past free-response questions for the Computer Science exam in Java. It provides detailed Java code examples alongside notes that explain key assumptions, such as preconditions, boundary cases, and recursion alternatives. The chapter demonstrates how to structure iterative and conditional logic, manipulate strings for usernames, update object state safely, compare records across collections, and compute scoring rules based on grid row colors.

LanguageEnglish

CategoryExam

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Chapter 5: Annotated Solutions to Past Free-Response Questions

Question 1

Part (a)

Part (b)

Question 2

Question 3

Question 4

Ninth Edition Be Prepared for the Computer Science Exam in Java Chapter 5: Annotated Solutions to Past Free-Response Questions 2026 Maria Litvin Phillips Academy, Andover, Massachusetts Gary Litvin Skylight Publishing, Andover, Massachusetts Skylight Publishing Andover, Massachusetts Copyright © 2026 by Maria Litvin, Gary Litvin, and Skylight Publishing All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the authors and Skylight Publishing. ISBN 978-0-9972528-3-5 Skylight Publishing 14 Lincoln Street Andover, MA 01810 web: [www.skylit.com](www.skylit.com) e-mail: [sales@skylit.com](sales@skylit.com) [support@skylit.com](support@skylit.com) [www.skylit.com/beprepared/x2026all.zip](www.skylit.com/beprepared/x2026all.zip contains)[ contains](www.skylit.com/beprepared/x2026all.zip contains)[ ](www.skylit.com/beprepared/x2026all.zip contains)complete Java code, including solutions and test programs for runnable projects. The free-response questions for this exam are posted on AP Central: [https://apcentral.collegeboard.org/courses/ap-computer-science-a/exam/past](https://apcentral.collegeboard.org/courses/ap-computer-science-a/exam/past)exam-questions Scoring guidelines for teachers are usually posted over the summer. Question 1 Part (a) public Account(String requestedName) { int num = 1; username = requestedName; while (!isAvailable(username)) { username = requestedName + num; 1 num++; } } Notes: 1. Not username += num; Part (b) public String getShortenedName() { String result = username; int pos = 0; while (pos >= 0) 1 { pos = result .indexOf("-"); if (pos >= 0) result = result .substring(0, pos-1) + result .substring(pos+1); } return result;} 2 Notes: 1. According to the method’s precondition, pos cannot be 0—only negative or greater than 0. 2. A recursive solution: // Helper method: private String getShortenedName(String name) { int pos = name .indexOf("-"); if (pos < 0) return name; name = name .substring(0, pos-1) + name .substring(pos+1); return getShortenedName(name); } public String getShortenedName() { return getShortenedName(username); } Question 2 public class Bottle { private final double capacity; private double amount; public Bottle(double cap) { capacity = cap; amount = capacity;} public double updateAmount(double { amount - = amtToBeRemoved; if (amount < 0 .25*capacity) amount = capacity; return amount;} } Notes: 1. Do not recheck the given preconditions. amtToBeRemoved) 1 Question 3 public int moreHistoryThanMathAbsences() { int numStudents = 0; for (CourseRecord histRec : historyList) { for (CourseRecord mathRec : mathList) 1 { if (histRec.getStudentID() .equals(mathRec.getStudentID()) && histRec.getAbsences() > mathRec.getAbsences()) { numStudents++; } } } return numStudents;} Notes: 1. An ArrayList has the indexOf method. However, to use it here on mathList, we have to be sure that the CourseRecord class has the appropriate equals method defined. This is not guaranteed, so you might lose points if you use mathList’s indexOf. It is safer to use nested loops. Question 4 public int getPointsForRow(int targetRow) { boolean sameColor = true; String prevColor = ""; 1 int points = 0; for (int col = 0; col < board[targetRow] .length; col++){ Space sp = board[targetRow][col]; points += sp .getPoints(); String color = sp .getColor(); if (col > 0 && !color .equals(prevColor)) sameColor = false; prevColor = color; } if (sameColor) points *= 2; return points; } 2 Notes: 1. Can be initialized to null or any String value. 2. Alternative solution, with a “for-each” loop: public int getPointsFo

FAQs

What does Chapter 5 include for the Java exam?

It includes annotated solutions to past free-response questions, with Java code and explanatory notes for the required parts.

How does Question 1 handle the shortened username?

It iteratively removes the section around the first hyphen using indexOf and substring operations, and it also presents a recursive helper method as an alternative.

What scoring logic is used in Question 4?

The solution sums points across a target row and doubles the total when all spaces in the row share the same color.

Sep 22, 2026

Uploaded by Jacob