String anagram in Java

Question

i am trying to create a program for string anagram that follows these conditions:

1. method should allow only letters, white space, commas and dots in an anagram. If there are any other characters, then the string cannot contain an anagram.
2. The method should ignore all white space, commas and dots when it checks the text.
3. If there are no letters in the text, then the text cannot be an anagram.

import java.util.Arrays;
import java.util.Scanner;

public class StringAnagram {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        System.out.print("Enter first string: ");
        String first = in.nextLine().toUpperCase();


        System.out.print("Enter second string: ");
        String second = in.nextLine().toUpperCase();

        String result = isAnagram(first, second);
        System.out.println(result);
    }

private static String isAnagram(String first, String second) {
    String answer = "";


    if (first.matches("[A-Z\\.\\,\\s]")) {
        String st = first.replaceAll("\\.\\,\\s", "");
        String nd = second.replaceAll("\\.\\,\\s", "");
        char[] arraySt = st.toCharArray();
        char[] arrayNd = nd.toCharArray();
        Arrays.sort(arraySt);   
        Arrays.sort(arrayNd);

            if(Arrays.equals(arraySt, arrayNd)) {
                answer = "Anagram.";
            }

            else {
                answer = "No anagram.";
            }
        }

    else  {
        answer = "No anagram.";
    }
    return answer;
}
}

However when the program tests these 2 sentences, they are not anagram but they should be anagram. I have no idea where to look for mistake.

1. Eleven plus two is thirteen.
2. Twelve plus one is thirteen.

Answer 1

If you start your method as follows, it will fulfil validations mentioned in the 1st and the 3rd points of your question:

if (first == null || second == null || first.equals("") || second.equals("") || !first.matches("[A-Za-z,. ]+")
        || !second.matches("[A-Za-z,. ]+")) {
    return "No anagram.";
}

The next thing you should do is to replace all white space, commas and dots with "" in order to ignore them:

String st = first.replaceAll("[,. ]+", "");
String nd = second.replaceAll("[,. ]+", "");

The complete code is as follows:

private static String isAnagram(String first, String second) {
    if (first == null || second == null || first.equals("") || second.equals("") || !first.matches("[A-Za-z,. ]+")
            || !second.matches("[A-Za-z,. ]+")) {
        return "No anagram.";
    }
    String answer = "";

    String st = first.replaceAll("[,. ]+", "");
    String nd = second.replaceAll("[,. ]+", "");

    if (st.equals("") || nd.equals("")) {
        return "No anagram.";
    }

    char[] arraySt = st.toCharArray();
    char[] arrayNd = nd.toCharArray();
    Arrays.sort(arraySt);
    Arrays.sort(arrayNd);

    if (Arrays.equals(arraySt, arrayNd)) {
        answer = "Anagram.";
    } else {
        answer = "No anagram.";
    }
    return answer;
}

A test run:

Enter first string: london
Enter second string: britain
No anagram.

Another test run:

Enter first string: ram
Enter second string: mar
Anagram.

Another test run:

Enter first string: .
Enter second string: .
No anagram.

Another test run:

Enter first string: ,
Enter second string: .
No anagram.

Another test run:

Enter first string: ra.m
Enter second string: a.m.r
Anagram.