What is the output when the following program is executed?

public class Main {
    public static boolean isPalindrome(String s) {
        if(s.length() <= 1)
            return true;
        if(s.charAt(0) != s.charAt(s.length() - 1))
            return false;
        return isPalindrome(s.substring(1, s.length()-1));
    }
    public static void main(String[] args) {
        System.out.println(isPalindrome("radar"));
    }
}