Access Modifiers

Access modifiers control who can see and use your variables and methods.

The Three Main Types

public class Robot {
    public String name;        // Any class can access
    private DcMotor motor;     // Only this class can access
    protected double speed;    // This class and subclasses can access
}

Public

Everyone can access it:

public void moveForward() {
    // Other classes can call this method
}

Robot myRobot = new Robot();
myRobot.moveForward(); // This method can get called from any other class

Private

Only the same class can access it:

private DcMotor leftMotor;

private void calibrateMotors() {
    // Only methods in this class can call this
}

// myRobot.calibrateMotors(); // This won't work from outside the class

Protected

Same class and subclasses can access it:

protected double maxSpeed = 1.0;

// Useful when one class extends another
public class AdvancedRobot extends Robot {
    public void turbo() {
        maxSpeed = 1.5; // Can access parent's protected variables
    }
}

Quick Reference

Modifier	Who Can Access	When to Use
public	Everyone	Methods others should call, constants
private	Only this class	Internal details, helper methods
protected	This class + subclasses	Shared with child classes