Java Regex First Name Validation

I understand that validating the first name field is highly controversial due to the fact that there are so many different possibilities. However, I am just learning regex and in an effort to help grasp the concept, I have designed some simple validations to create just try to make sure I am able to make the code do exactly what I want it to, despite whether or not it conforms to best business logic practices.

I am trying to validate a few things.

1. The first name is between 1 and 25 characters.
2. The first name can only start with an a-z (ignore case) character.
3. After that the first name can contain a-z (ignore case) and [ ‘-,.].

4. The first name can only end with an a-z (ignore case) character.

   public static boolean firstNameValidation(String name){
   
       valid = name.matches("(?i)(^[a-z]+)[a-z .,-]((?! .,-)$){1,25}$");
   
       System.out.println("Name: " + name + "nValid: " + valid);
   
       return valid;
    }
   

Answer

Your expression is almost correct. The following is a modification that satisfies all of the conditions:

valid = name.matches("(?i)(^[a-z])((?![ .,'-]$)[a-z .,'-]){0,24}$");