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) Delivering the MVP Validation

I completely din't und the Challenge.Plss help

I din't understand what to do in this challange.

public class TeacherAssistant {
   String firstName;

  public static String validatedFieldName(fieldName) {
      throw new IllegalArgumentException ("A letter is required");
    fieldName =Character.toLowerCase(firstName);

    // 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;


1 Answer

Michael Hess
Michael Hess
24,511 Points

Hi Alina,

This challenge wants us to make sure a member field begins with a lowercase m and that the second character in the member field is an uppercase letter. Please see the following code:

if (fieldName.startsWith("m") && Character.isUpperCase(fieldName.charAt(1))) {
      return fieldName;
    } else {
      throw new IllegalArgumentException("Invalid field name");

If you have any questions feel free to ask them!