Java Programming Basics

Overview

Java is an object-oriented, general-purpose programming language. Everything in a Java program is organized into classes — blueprints that define objects made up of variables (data) and methods (behavior).

Java is the primary language used for FRC robot programming through the WPILib library.

Java is case sensitive

Int and int are different things. drivetrain and Drivetrain are different things. Capitalization always matters.

---

Common Keywords

These keywords appear constantly in Java code. Keep them in mind as you work through the sections below.

Keyword	Meaning
public	Accessible by any other class
private	Accessible only within the class it is declared in
protected	Accessible within the class and any subclasses
static	Belongs to the class itself, not a specific object
final	Cannot be changed after it is first assigned
void	The method returns no value
return	Sends a value back to the caller and exits the method
null	Represents the absence of a value (nothing / empty)
new	Creates a new object from a class
this	Refers to the current object inside a class
extends	Inherits fields and methods from another class

---

Knowledge Check

Quiz results are saved to your browser's local storage and will persist between sessions.

Reset quiz

#

Java is case-sensitive, meaning Drivetrain and drivetrain are treated as different things.

True

False

Java distinguishes uppercase from lowercase everywhere — in class names, variable names, and keywords. Int is not the same as int.

#

What does the final keyword do when applied to a variable?

Marks the variable as publicly accessible

Prevents the variable from being reassigned after it is first set

Makes the variable available to all classes

Hides the variable from subclasses

final locks the variable's value. Once assigned, it cannot be changed — useful for constants like motor port numbers that should never move.

#

In Java, a class is best described as:

A single executable statement

A list of import statements

A blueprint that defines an object's fields and methods

A keyword that creates a new object

Classes are templates. You define the blueprint once, then use new to create as many objects from it as you need.

Quiz Progress

0 / 0 questions answered (0%)

0 correct

Quiz Complete!

0%

Reset quiz

---

What to Read Next

The following pages each cover one core concept in depth, with FRC-focused examples throughout:

• Variables and Data Types — types, constants, scope, operators, naming conventions
• Methods — declaring methods, return types, parameters, calling methods
• Classes and Objects — fields, constructors, inheritance, @Override

Quiz Progress

• Answered: 0 / 0 (0%)
• Correct: 0 / 0 (0%) Reset