Hi Tanguy, I have seen this problem come up a lot. You do not actually need a boolean to run your do while loop, and you can simplify it a lot by having the loop depend on the response directly. java // I have initialized a java.io.Console for you. It is in a variable named console. String response; do{ response = console.readLine("Do you understand do while loops?"); }while(response.equalsIgnoreCase("no")); You may also include your print statement that you included using if(response.equalsIgnoreCase("no")). HOWEVER, with all that being said, what you did actually works fine! You just made a typo in your code. You wrote invalidReponse not invalidReSponse, as declared outside your loop. You can see these errors easily if you check the compiler error (You would see a symbol not found error point to that variable) Hope that helps!

Because when you type a and hit Enter, then the in.read() method returns three characters - 'a', the character for carriage return \r and the character for line break ('\n'). (Note that the combination \r\n is considered as line-break under Windows).

Your program will have significantly different behavior if you run it under Linux or OSX, because line-breaking character(s) is specific to the OS you're running the program on. Under Linux, it will be \n, under OS X-9 it will be \r, for example.

As a work-around, you can read the whole line (by using a Scanner) and trim it, which will omit the line-breaking character (disregarding the OS type):

public static void main (String args[]) throws java.io.IOException {
      String line;
      Scanner sc = new Scanner(System.in);
      do {
          System.out.println("Please a key followed by ENTER:");
          line = sc.readLine().trim();
      } while (!"q".equals(line));
  }