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Quizzes > High School Quizzes > Technology

2020 APCSA Practice Exam Quiz

Enhance your APCSA skills with FRQ challenges

Difficulty: Moderate
Grade: Grade 11
Study OutcomesCheat Sheet
Paper art depicting trivia for AP Computer Science A FRQ Challenge 2020 practice quiz

Which of the following is the correct way to declare an integer variable in Java?
num int = 5;
int number: 5;
int number = 5;
integer number = 5;
Option A correctly uses the int keyword and the assignment operator to declare and initialize an integer variable. The other options use incorrect keywords or syntax that are not valid in Java.
What is the output of the following code snippet? System.out.println(3 + 4);
3+4
34
7
Error
The code computes the sum of 3 and 4, resulting in 7, and then prints that number. It does not perform string concatenation, so the other options are incorrect.
Which keyword is used to define a class in Java?
define
class
Class
new
In Java, the keyword 'class' is used to declare a new class. The other options either use incorrect capitalization or represent entirely different constructs.
Which method returns the number of characters in a Java String?
getLength()
size()
length()
count()
The correct method to determine the number of characters in a Java String is length(). The alternatives are either methods of other data structures or not defined in Java.
How do you start a single-line comment in Java?
#
//
/*
--
In Java, single-line comments begin with two forward slashes (//). The other options represent either multi-line comment syntax or comment styles from other programming languages.
Given an array of integers, which loop is most appropriate to iterate through all elements when you do not need the index?
traditional for loop
for-each loop
while loop
do-while loop
The for-each loop directly iterates over each element in an array without using an index, making it ideal when the index is not required. The other loop constructs are better suited when you need index control or more complex iteration logic.
Which of the following represents valid method overloading in Java?
public void display(int a) {} public void display(int b, int c) {}
public int display(int a) {} public double display(int a) { return 0.0; }
public void display() {} public void DISPLAY() {}
public void display(int a) {} public int display(int a) { return a; }
Option A shows two methods with the same name but different parameter lists, which is the correct approach to method overloading. Options B and D have methods differing only by return type, which is insufficient for overloading, while Option C relies solely on case differences, which is not permitted in Java.
Which of the following best describes encapsulation in object-oriented programming?
Combining two or more operations into a single method call
Hiding internal state and requiring all interaction to be performed through an object's methods
Changing the behavior of a method in a subclass
Inheriting properties from parent classes
Encapsulation is about restricting direct access to some of an object's components and forcing interaction through well-defined methods. This protects the internal state and maintains integrity by preventing external interference.
What will be the result of calling the constructor of a subclass in Java?
It requires manual invocation of the superclass constructor in all cases
It automatically calls the constructor of its superclass before executing its own body
It calls the main method of the superclass
It does not call the superclass constructor
When a subclass constructor is executed, Java implicitly calls the no-argument constructor of its superclass before executing the subclass's constructor body. This ensures proper initialization of the inherited properties.
Which access modifier makes a member accessible only within its own class?
public
default
protected
private
The 'private' access modifier ensures that a member is accessible only within the class in which it is declared. The other modifiers expose the member to a wider scope than intended.
Which keyword is used to refer to the current object's instance variable when there is a naming conflict?
self
super
instance
this
The 'this' keyword refers to the current object and helps distinguish the instance variable from a parameter with the same name. 'super' is used to reference a superclass, and the other terms are not valid in Java for this purpose.
Given the following method signature, public int compute(int x, int y), what is the method's return type?
compute
error
void
int
The method signature explicitly states that the return type is int, meaning the method will return an integer value. None of the other options match what is declared in the method signature.
Which of the following correctly demonstrates a for loop that prints numbers 1 to 5?
for (int i = 0; i <= 5; i++) { System.out.println(i); }
for (int i = 1; i < 5; i--) { System.out.println(i); }
for (int i = 1; i < 5; i++) { System.out.println(i); }
for (int i = 1; i <= 5; i++) { System.out.println(i); }
Option A correctly initializes and increments the loop variable to print numbers from 1 through 5. The other loops either have incorrect boundaries or decrements that prevent them from functioning as intended.
In Java, what is the result of integer division 7 / 2?
7/2
3.5
4
3
When performing integer division in Java, the fractional part is truncated, so 7 divided by 2 gives 3. The value 3.5 is not possible because both operands are integers.
Which interface must a class implement to allow its objects to be sorted using Arrays.sort() in Java?
Comparator
Comparable
Sort
Sortable
Implementing the Comparable interface enables a class to define a natural ordering that can be used by Arrays.sort(). While Comparator is useful for custom ordering, the class itself must implement Comparable to be sorted directly by this method.
Consider a recursive method that computes the factorial of an integer n. What is the critical component that prevents an infinite recursive loop?
The recursive call itself
An external counter variable
A base case that terminates recursion
A loop within the method
A base case is essential in every recursive method because it provides a condition under which the recursion terminates. Without it, the recursive calls would continue indefinitely, eventually causing a stack overflow.
Which of the following correctly overrides the equals method from the Object class?
public boolean equals() { /* implementation */ }
public int equals(Object obj) { /* implementation */ }
public boolean equals(Object obj) { /* implementation */ }
public boolean equals(MyClass obj) { /* implementation */ }
The equals method in Java must have the same signature as defined in the Object class, which is public boolean equals(Object obj). The other options either use an incorrect parameter type, an incorrect return type, or omit parameters entirely.
In Java, if a variable is declared as static, which statement is true?
The variable is shared among all instances of the class
The variable can only be accessed within its class
The variable must be final as well
Each instance of the class gets its own copy of the variable
A static variable is shared across all instances of a class, meaning there is only one copy regardless of how many objects are created. The other options do not accurately describe the properties of static variables in Java.
Which of these best practices helps avoid NullPointerExceptions in Java?
Avoid using try-catch blocks
Rely on automatic initialization of object references
Declare all objects as public
Always check if an object is null before accessing its methods
Performing a null check before accessing an object's members is a common defensive programming technique that prevents NullPointerExceptions. This proactive approach is more effective than relying on automatic initialization or inappropriate use of error handling.
In a Java program, which of the following scenarios best demonstrates polymorphism?
A class having multiple constructors
A superclass reference holding an object of a subclass
Two methods in the same class having the same name but different parameters
A method that calls itself recursively
Polymorphism in Java is often demonstrated by using a superclass reference to refer to an object of a subclass, which allows method overriding to determine behavior at runtime. The other options describe method overloading, constructor variability, and recursion, which are not direct examples of polymorphism.
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Study Outcomes

  1. Apply object-oriented programming principles to design and implement Java classes and methods.
  2. Analyze code segments to identify logical errors and optimize performance.
  3. Evaluate algorithm efficiency using key coding constructs such as loops and conditionals.
  4. Debug and troubleshoot code by systematically tracing program logic.
  5. Synthesize problem solutions that integrate multiple coding concepts effectively.

2020 APCSA FRQ Practice Exam Cheat Sheet

  1. Know the Exam Blueprint - The AP Computer Science A exam is split into multiple-choice and free-response parts, each counting for half of your total score. Understanding this balance lets you plan for both speed and depth. Approach practice tests like a treasure hunt and track your progress to level up! APStudy Exam Guide
  2. Clean Code Habits - Writing clear, organized code is like speaking the computer's native language - use meaningful variable names, proper indentation, and comments to keep your logic crystal clear. Always sketch out your solution steps on paper before typing to avoid messy bug hunts later. College Board Exam Tips
  3. Java Quick Reference Savvy - Keep the Java Quick Reference guide close at hand; it lists library methods you can legally use on exam day. Familiarity with these will save you from panicking over forgotten syntax. Bookmark key classes like Math, String, and ArrayList to impress the graders! Java Quick Reference
  4. Core Programming Concepts - Master primitive types, boolean logic, conditionals, loops, classes, arrays, ArrayLists, 2D arrays, inheritance, and recursion - these are your AP CSA bread and butter. Think of each concept as a puzzle piece; the more you practice, the sharper your problem-solving picture becomes. APStudy Quick Topics
  5. Constructor Craftsmanship - Constructors set the stage for every object by defining its initial state, and you call them with the 'new' keyword like a VIP pass. Forgetting or misusing them is like showing up to a costume party without a costume - awkward! Play with different constructor patterns to build your confidence. AP CSA Review Topics
  6. Wrapper Wisdom - Wrapper classes like Integer and Double let you treat primitives as objects, unlocking handy methods and collections compatibility. Autoboxing and unboxing happen behind the scenes, so knowing when they kick in helps you avoid unwelcome surprises. Think of it as the difference between a paper ticket and a digital pass - both get you in, but they behave differently! AP CSA Review Topics
  7. Array Traversal Techniques - Practice looping through arrays with for‑loops, while‑loops, and the nifty enhanced for‑loop to spot the scenario where each shines. Picture your loop as a conveyor belt - choose the right speed and style to inspect every item efficiently. Consistent practice turns this task into second nature! Sly Academy Notes
  8. Inheritance Insights - Inheritance lets subclasses borrow from superclasses, saving you from rewriting code and boosting your design skills. Override methods for customization and invoke the super keyword to keep parent logic intact. It's like being part of an epic family legacy - embrace it! AP CSA Review Topics
  9. Recursion Rules - Recursion is a method calling itself - think of it as a set of nested Russian dolls with a base case as the smallest doll. Compare it to iteration to pick the best tool for each problem and avoid infinite loops! Master both to become a coding wizard. AP CSA Review Topics
  10. Free‑Response Practice - Tackle past free-response questions to familiarize yourself with the exam's format, wording, and time constraints. Treat each prompt like a mini-game and reflect on feedback to sharpen your written solutions. With repeated playthroughs, you'll turn exam stress into exam success! College Board Exam Tips
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