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Java Java Objects (Retired) Delivering the MVP Validation

help with exercise needed

i tried to solve this exercise but my solution does not work, can somebody please show me the answer?

public class TeacherAssistant {

  public static String validatedFieldName(String fieldName) {
    // 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
      throw new IllegalArgumentException("Member fields must start with an 'm'");
      throw new IllegalArgumentException("second letter must be uppercased!");

    return fieldName;


1 Answer

3,655 Points

You need to use charAt method instead of indexOf. Here are some good answers how to solve this: https://teamtreehouse.com/community/trying-to-get-the-letter-to-at-specific-position-to-work-but-cant-figure-it-outplease-help https://teamtreehouse.com/community/java-objects-validation-this-ones-tricky

Hope this helps!

p.s. If you write a long version code you have to check also possibility that second character is letter (or rather is not a letter as you need to throw Illegal Argument Exception if it isn't) otherwise you will fail the test. Don't think they have the same problem with shorter code versions.