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Java Java Objects Harnessing the Power of Objects Overload Methods

Ensure you use the += shorthand to increment lapsDriven by the new laps argument.

before I had public void drive() { lapsDriven++; barCount--; } now in this excersice they want me to rewrite the method. so i have public void drive() { drive (MAX_BARS); }

public void drive(int lapsDriven) { lapsDriven++; }

not sure what to do.

class GoKart {
  public static final int MAX_BARS = 8;
  private String color;
  private int barCount;
  private int lapsDriven;

  public GoKart(String color) {
    this.color = color;

  public String getColor() {
    return color;
  public void charge() {
    barCount = MAX_BARS;

  public boolean isBatteryEmpty() {
    return barCount == 0;

  public boolean isFullyCharged() {
    return MAX_BARS == barCount;

  public void drive() {

  public void drive(int lapsDriven) {

3 Answers

J.D. Sandifer
J.D. Sandifer
18,813 Points

Your problem is here:

  public void drive(int lapsDriven) {

You're incrementing by one instead of adding the amount in the parameter lapsDriven. Read the title of your question and follow its direction.

(You should really change your parameter to a more helpful name like int lapsToDrive, too. That will make the code less confusing to read and write and will allow you to avoid the this identifier.)

Here's how you increment a variable using +=:

Note: this is just an example

int score = 100
score += 10

After this code is run, score will be 110 because I incremented score by 10. The code above is the same as saying:

int score = 100
score = score + 10

It seems like the challenge wants you to increment the lapsDriven variable by 1.

I hope you understand. ~Alex

Fixed the issue. Thank you for answering the question. public void drive(int lapsToDrive) { lapsDriven+=lapsToDrive; barCount-=lapsToDrive; }