Six String example

foo.java

public class foo {
    public static void main(String[] args) throws Exception {
        String long_string = "asdfasdf123456";
        String six_string = "123456";
        String five_string = "12345";

        String one_string = "1";
        String empty_string = "";

        System.out.println(six_string(long_string));
        System.out.println(six_string(six_string));
        System.out.println(six_string(five_string));
        System.out.println(six_string(one_string));
        System.out.println(six_string(empty_string));
        
    }
    
    public static String six_string(String str){
        return str.substring(Math.max(0, str.length()-6), str.length());
    }
}