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Java Java Objects Harnessing the Power of Objects Handling Exceptions


it said "java.util.MissingFormatArgumentException: Format specifier '%s'" what dose that mean?

class Example {

  public static void main(String[] args) {
    GoKart kart = new GoKart("purple");
     if (kart.isBatteryEmpty()) {
       System.out.println("The battery is empty");
    try {
      System.out.println("Example.java contains a program using the GoKart class we have been building (included for you to reference).");
    } catch (IllegalArgumentException iae) {
      System.out.println("please charge!");
      System.out.printf("the error was %s");

class GoKart {
  public static final int MAX_BARS = 8;
  private int barCount;
  private String color;
  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) {
    if (laps > barCount) {
      throw new IllegalArgumentException("Not enough battery remains");
    lapsDriven += laps;
    barCount -= laps;


1 Answer

As with many languages semicolons terminate statements and arguments are placed inside parentheses.

This makes iae.getMessage(); 'missing' from printf() here:

System.out.printf("the error was %s");

You should use a comma instead and include iae.getMessage() inside the parentheses:

System.out.printf("the error was %s", iae.getMessage());