How to replace all characters in a Java string with stars

Question

I want to replace all the characters in a Java String with * character. So it shouldn\'t matter what character it is, it should be replaced with a *

Answer 1

There may be other faster/better ways to do it, but you could just use a string buffer and a for-loop:

public String stringToAsterisk(String input) {
    if (input == null) return "";

    StringBuffer sb = new StringBuffer();
    for (int x = 0; x < input.length(); x++) {
        sb.append("*");
    }
    return sb.toString();
}

If your application is single threaded, you can use StringBuilder instead, but it's not thread safe.

I am not sure if this might be any faster:

public String stringToAsterisk(String input) {
    if (input == null) return "";

    int length = input.length();
    char[] chars = new char[length];
    while (length > 0) chars[--length] = "*";
    return new String(chars);
}