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Java Java Objects (Retired) Delivering the MVP Validation

Abhishek Gangadhar
Abhishek Gangadhar
9,467 Points

Isn't this valid?? I need to throw an exception if the second character is not in uppercase

I have used the isLowerCase() method to check if the character at index 1 i.e. the second character is in lower case or not. i'm getting an error "cannot identify Symbol"

TeacherAssistant.java
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
    if(fieldName.indexOf(0)!='m'){
      throw new IllegalArgumentException("The first letter must be m");
    }
    if(isLowerCase(fieldName.charAt(1)))
      throw new IllegalArgumentException("Following m must be a Upper Case Letter");
    return fieldName;
  }

}

2 Answers

Kevin Faust
Kevin Faust
15,353 Points

Hey Abhishek,

Your really really close. Just 2 minor things:

fieldName.indexOf(0)!='m'

We're actually supposed to use charAt(0) because we are checking the position of a char. indexOf() is when you pass in a char and it returns the index value of that char. However we are doing the opposite so we use charAt.

Secondly, it should be Character.isLowerCase() because that method is part of the Character class and we must tell the compiler that. Otherwise it will be confused

I hope this helped and you learned something new :)

Dont forget to mark as best answer so others with the same question can see

Happy coding and best of luck,

Kevin

There's another problem, if the second character is a symbol. To fix this, you must test the character using

"Character.isLetter(charAt(0));"

You can add this on to the isLowerCase test, using an "or" statement (||)