Changes the string values to * the position after all of 'n'th characters

gistfile1.java

public class Main {

    // Returns the string which changed all characters after 'n'th to *
    public static String strToStar(String s, int n) {
        return s.substring(0, n)
            + new String(new char[s.length() - n])
                .replace("\0", "*");
    }

    // Test
    public static void main(String[] args) {
        String result = strToStar("abcdefg", 2);
        $.pn(result);
    }

}

[Result]
ab*****