Палиндром

public class Main {
    public static void main(String[] args){
        String text = "Madam, I'm Adam!";
        //String text = "Hello, World!";
        if (text==null){
            System.out.println("empty");
            return;
            }
        else {
            StringBuilder s = new StringBuilder((text.toLowerCase()).replaceAll("[^A-Za-z1-9]+", ""));
        String s1 = s.toString();
        StringBuilder sr = s.reverse();
        String s2 = sr.toString();
        System.out.println(s1);
        System.out.println(s2);
        System.out.println(s1.equals(s2));
        }
    }
}