Why are we using void in "public Void charge(){" is it because the variable charge has an integer value?

code should be:

public class GoKart { //Declare a Public Class for the Object GoKart
  private String mColor; //Declare a private variable, car color as a string

  public static final int MAX_ENERGY = 8; //Public but fixcd integer value for the max energy
  private int mBarsCount; //Declare Private variable Bar count
  public GoKart(String color) { // Declare the objects color
    mColor = color; //member color is the variable 
    mBarsCount = 0; //fixed starting value

  }

  public String getColor() {
    return mColor;
  } 
  public void charge() { //Beacuse it is a integer use void?
     mBarsCount =  MAX_ENERGY;
  }
}

void in method declaration means that nothing is returned from that method.

To understand why we use "void" requires us to better understand methods and their signatures.

The first line of a method is called a method signature. In your case, the method signature is

public void charge()

The three parts that make up this signature are

1. "public". We can use public (any other class or method can use this method), or private (only methods inside of our class can use this method)
2. "void". Methods can perform a function, and maybe write to the console. Or, they can return something back to the place that called the method. By using void you are saying you only want the method to perform a function, and maybe print to the console. Below I demonstrate returning an int.
3. "charge()". The method name, charge() is the last part of a method signature.

public static void main(String[] args) {

    //here I declare an int x
    int x;

    //here i assign the variable x to the returned value of add()
    x = add(3, 6);

    console.print(x);
}
public int add(int firstNumber, int secondNumber) {
    //because I used "int" and not void in the method signature I must have a return 
    //statement like the one below. This will return a number (the 2 numbers added) 
    //and in the main method above it will be assigned to x
    return firstNumber + secondNumber;
}

The console will then print out "9", because 3 + 6 = 9. If I tried doing this with a void in the method signature I would get an error.