AP®︎ Computer Science A Unit 1: Notes & Study Guide

Prepare for your quiz, test, or the AP exam with a comprehensive review on Unit 1 of AP Computer Science A – Using Objects and Methods.

Exam weight: 15–25%
15 Topics

Unit 1: Using Objects and Methods

This unit introduces the fundamentals of Java programming, including primitive data types, expressions, variables, objects, and methods used to represent and manipulate data.

Begin with Topic 1.1: Introduction to Algorithm...

To review Unit 1, go through each of the 15 topics below.

Everything you actually need to know for your Unit 1 test, pulled directly from the AP® Computer Science A curriculum.

Topic 1.1
~7 min
Review
Introduction to Algorithms, Programming, and Compilers
Introduction to Algorithms, Programming, and Compilers
  • What an Algorithm Is
  • From Java Code to Execution
  • Types of Programming Errors
Review
Topic 1.2
~6 min
Review
Variables and Data Types
Variables and Data Types
  • What Data Types and Variables Are
  • Primitive vs Reference Types
  • Declaring and Initializing Variables
Review
Topic 1.3
~6 min
Review
Expressions and Output
Expressions and Output
  • Generating Output with print and println
  • String Literals and Escape Sequences
  • Arithmetic Expressions in Java
Review
Topic 1.4
~6 min
Review
Assignment Statements and Input
Assignment Statements and Input
  • What Assignment Statements Do
  • How Expressions Evaluate
  • Initialization, Reassignment, and null
Review
Topic 1.5
~7 min
Review
Casting and Range of Variables
Casting and Range of Variables
  • Casting Betweenintanddouble
  • Automatic Widening and Integer Division
  • Rounding a double to the Nearest int
Review
Topic 1.6
~5 min
Review
Compound Assignment Operators
Compound Assignment Operators
  • What Compound Assignment Operators Do
  • The Five Compound Assignment Operators
  • Increment and Decrement Operators
Review
Topic 1.7
~6 min
Review
Application Program Interface (API) and Libraries
Application Program Interface (API) and Libraries
  • What an API Is and How Libraries Are Organized
  • Attributes vs Behaviors in an API Class
  • Reading an API Method Signature Correctly
Review
Topic 1.8
~6 min
Review
Documentation with Comments
Documentation with Comments
  • What Comments Are and Why They Matter
  • The Three Types of Comments in Java
  • Preconditions and Postconditions
Review
Topic 1.9
~7 min
Review
Method Signatures
Method Signatures
  • What a Method Signature Is
  • Parameters vs Arguments and Call by Value
  • Void vs Non-Void Methods and How to Call Them
Review
Topic 1.10
~5 min
Review
Calling Class Methods
Calling Class Methods
  • What Class Methods Are
  • How to Call Static Methods
  • Static vs Instance Methods
Review
Topic 1.11
~5 min
Review
Math Class
Math Class
  • What the Math Class Is and How You Use It
  • The Math Methods You Must Know
  • Generating Random Numbers in a Range
Review
Topic 1.12
~5 min
Review
Objects: Instances of Classes
Objects: Instances of Classes
  • What a Class Is vs What an Object Is
  • Classes as Types and Object Instantiation
  • Reference Variables and Memory
Review
Topic 1.13
~7 min
Review
Object Creation and Storage (Instantiation)
Object Creation and Storage (Instantiation)
  • What Constructors Are and How They Are Identified
  • Object References and Variable Declarations
  • Creating Objects with new
Review
Topic 1.14
~5 min
Review
Calling Instance Methods
Calling Instance Methods
  • What Instance Methods Are
  • How to Call an Instance Method
  • Instance vs Static Methods
Review
Topic 1.15
~6 min
Review
String Manipulation
String Manipulation
  • What a String Is
  • Concatenation and Combining Strings
  • String Indexing and Valid Ranges
Review

Notes

1 credit used · 5/5 remaining