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Java Java Objects (Retired) Harnessing the Power of Objects Throwing Exceptions

Not accepting my code

There is always a statement appears "Are you sure you threw the IllegalAmountException if requested amount of laps would make battery less than zero" , but i think i have done it correctly (taking (laps< 0 ) in "if" statement). why doesn't it work?

public class GoKart {
  public static final int MAX_BARS = 8;
  private String mColor;
  private int mBarsCount;

  public GoKart(String color) {
    mColor = color;
    mBarsCount = 0;

  public String getColor() {
    return mColor;

  public void drive(int laps) {
    // Other driving code omitted for clarity purposes
   if (laps<0){
     throw new IllegalArgumentException("Not enough battery remains");
    mBarsCount -= laps;
   public void drive() {

  public void charge() {
    while (!isFullyCharged()) {

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

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


1 Answer

Dan Johnson
Dan Johnson
40,532 Points

While sending in negative laps probably is a good candidate for throwing an IllegalArgumentException the challenge is wanting you to check and see if the result of mBarsCount - laps is negative, i.e. you're trying to drive more laps than you have power for.