Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Objects Harnessing the Power of Objects Handling Exceptions

%s

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

Example.java
class Example {

  public static void main(String[] args) {
    GoKart kart = new GoKart("purple");
     if (kart.isBatteryEmpty()) {
       System.out.println("The battery is empty");
    }
    try {
     kart.drive(42);
      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");
                       iae.getMessage();
    }
  }

}
GoKart.java
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() {
    drive(1);
  }

  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");
                       iae.getMessage();

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

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