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Java Java Objects Harnessing the Power of Objects Throwing Exceptions

Why is IllegalArgumentException not working?

I'm not sure why I'm not understanding this one fully. I put an if statement, but I don't understand why its not correct.

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 laps) {
   lapsDriven += laps;
    barCount -= laps;
      throw new IllegalArgumentException("Not enough energy bars to support laps request");


1 Answer

Steven Parker
Steven Parker
229,608 Points

You have the right idea, but the test needs to check if the energy (barCount) is less than the laps.

Also, the testing needs to be done before any changes are made to the variables.