How to use Scanner to read silently from STDIN in Java?

Question

I want to make a Java program that reads a Password from STDIN silently. I mean, without outputting any pressed chars to the terminal and keeping it hidden from commandline

Answer 1

A less secure option to get the password via STDIN that works with background jobs, virtual consoles, and normal consoles:

This is more compatible and less secure, it should work with your virtual console in your IDE, for background processes that don't have a TTY, and normal consoles. When a console is not found, it falls back to use a BufferedReader which will expose the password to screen as the user types it in some cases.

Java Code:

import java.io.*;
public class Runner {
    public static void main(String[] args) {
        String username = "Eric";

        try {
            ReadMyPassword r = new ReadMyPassword();
            char[] password = r.readPassword(
              "Hey %s, enter password to arm the nuclear wessels>", username);

            System.out.println("Exposing the password now: '" + 
                new String(password) + "'");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
class ReadMyPassword{
    public char[] readPassword(String format, Object... args)
            throws IOException {
        if (System.console() != null)
            return System.console().readPassword(format, args);
        return this.readLine(format, args).toCharArray();
    }
    private String readLine(String format, Object... args) throws IOException {
        if (System.console() != null) {
            return System.console().readLine(format, args);
        }
        System.out.print(String.format(format, args));
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                System.in));
        return reader.readLine();
    }
}

Here's what it looks like through through the Eclipse virtual console:

Hey Eric, enter password to arm the nuclear wessels>12345
Exposing the password now: '12345'
Program Sisko 197 ready for implementation on your command

Here's what it looks like through the normal console.

el@apollo:/home/el/bin$ java Runner
Hey Eric, enter password to arm the nuclear wessels>
Exposing the password now: 'abcdefg'
Program Sisko 197 ready for implementation on your command
el@apollo:/home/el/bin$