Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Java Java Objects (Retired) Harnessing the Power of Objects Incrementing

Charging the GoKart

Help how to solve this please.

Bummer! Use ++ to increment mBarsCount

By the way, is it just me or is the workspace console and objectives console really buggy?

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

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

  public String getColor() {
    return mColor;

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

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

  public void charge(){
      mBarsCount ++;


1 Answer

Stone Preston
Stone Preston
42,016 Points

the postfix ++ operator conventionally goes directly after the name of the variable. you have a space between them

 public void charge(){

Thank you very much that works. Seems inconsistent though. Sometimes we can write

aVariable = 0 


aVariable ++
aVariable +=1

are not allowed.

Anyway thanks very much I will be more careful in future