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Java Java Objects (Retired) Delivering the MVP Validation

Saad Ahmed
Saad Ahmed
7,090 Points

I keep getting this error: "Expected "m_first_name" to fail but it passed

Why wont this pass?

public class TeacherAssistant {

  public static String validatedFieldName(String fieldName) {
    char m_first_name = fieldName.charAt(0);
    char secondLetter = fieldName.charAt(1);

    if (m_first_name != 'm') {
      throw new IllegalArgumentException("Not valid, first letter should be 'm'.");
    if(secondLetter != Character.toUpperCase(secondLetter)) {
      throw new IllegalArgumentException("Second letter should be captitalized");
    // These things should be verified:
    // 1.  Member fields must start with an 'm'
    // 2.  The second letter in the field name must be uppercased to ensure camel-casing
    // NOTE:  To check if something is not equal use the != symbol. eg: 3 != 4
    return fieldName;


3 Answers

Hi Saad,

you also have to check if secondLetter is actually a letter but you are only checking if secondLetter is uppercased. After you fixed that you should be good to go.

Craig Dennis
Craig Dennis
Treehouse Teacher

You should also change your variable back to firstLetter to help remove your confusion. Looks great!

private char validateGuess(char letter) {
    if (!Character.isLetter(letter)) {
      throw new IllegalArgumentException("A letter is required."
    letter = Character.toLowerCase(letter);
    if (mMisses.indexOf(letter) >= 0 || mHits.indexOf(letter) >= 0) { 
      throw new IllegalArgumentException(letter + " has already been guessed")           }
    return letter;
  • The above code is the example to follow.
  • We care about charAt for this challenge, rather than indexOf
  • In pseudocode, we want to check for the following condition, and throw an error: " if the character at index 0 of fieldName does not equal 'm' OR the character at index 1 of fieldName is not upper case"