I do not understand why this is failing.

public class TeacherAssistant {

  public static String validatedFieldName(String fieldName) {
    // These things should be verified:
    // 1.  Member fields must start with an 'm'
    if (fieldName.indexOf('m') > 0 || fieldName.indexOf('m') < 0){
      throw new IllegalArgumentException();
    }

    // 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
    char secondLetter = fieldName.charAt(1);
    if (secondLetter != Character.toUpperCase(secondLetter))
    {
      throw new IllegalArgumentException();
    }
    return fieldName;
  }

}