Is the string palindrome?

Palindrome.java

public class Palindrome {
    public static void main(String[] args) {
        isPalindrome("Madam, I'm Adam!");
    }

    /*public static boolean isPalindrome(String text) {
        text = text.toLowerCase().replaceAll("[^a-zA-Z0-9]", "");
        String sb = new StringBuilder(text).reverse().toString();
        System.out.println(text);
        return sb.equalsIgnoreCase(text);
    }*/

    private static boolean isPalindrome(String str) {
        if (str == null)
            return false;
        StringBuilder strBuilder = new StringBuilder(str);
        strBuilder.reverse();
        return strBuilder.toString().equals(str);
    }
}