Member variable checker

It looks like you've written a method to handle returning the second letter and there are a few problems with that.

1 - You've defined the secondLetter() method inside the validatedFieldName() method. Move it outside the validatedFieldName() method.

2 - You've put the call to secondLetter() inside single quotes. You need to remove those. You also need parenthesis after the call.

3 - The variable fieldName is not available inside the secondLetter() method. You need to pass that in. Also, you need to change the method's signature to let the compiler know that this method is accepting a String argument.

4 - Since you are calling the secondLetter() method from inside a static method you need to declare it as static as well.

5 - You need quotes around m.

6 - The if statement is missing a closing parenthesis.

Here's the code:

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.charAt(0) != 'm' || !(Character.isUpperCase(secondLetter(fieldName)))) {
      throw new IllegalArgumentException("Wrong Syntax.");
    }

    return fieldName;
  }

  public static char secondLetter(String fieldName){
    return fieldName.charAt(1);
  }

}