help me///

Hi Jinhwa,

You aren't using a try/catch here - you're throwing the exception (it'll be caught elsewhere). You have two things to test; the first character is a lowercase 'm' and the second character is capitalised. So, IF those two things are true, return the fieldName ELSE throw the exception.

My code came out something like this:

public static String validatedFieldName(String fieldName) {

  if(fieldName.charAt(0) == 'm' && Character.isUpperCase(fieldName.charAt(1))) {
     // both things are true - do whatever success looks like
     return fieldName;
  } else {
     throw new IllegalArgumentException("This does not meet the requirements!");
  }
  // you could put the return line here
}

Although there are other ways of structuring this. The return statement can be outside of the if statement. If the true part is called, where the return is now, that means the else won't run. The tests are binary & mutually exclusive. So, the return can be after the if statement. You could negate both tests and have no else clause, perhaps! There are different solutions to this.

I hope that helps.

Steve.