System.console() returns null

I was using readLine of BufferedReader to get input/new password from user, but wanted to mask the password so I am trying to use java.io.Console class. Problem is that System.console() returns null when an application is debugged in Eclipse. I am new to Java and Eclipse not sure is this the best way to achieve? I am right clicking on the source file and selecting "Debug As" > "Java Application". Is there any workaround?

This is a bug #122429 of eclipse

This code snippet should do the trick:

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();
}

private char[] readPassword(String format, Object... args)
        throws IOException {
    if (System.console() != null)
        return System.console().readPassword(format, args);
    return this.readLine(format, args).toCharArray();
}

While testing in Eclipse, your password input will be shown in clear. At least, you will be able to test. Just don't type in your real password while testing. Keep that for production use ;).

System.console() returns null if there is no console.

You can work round this either by adding a layer of indirection to your code or by running the code in an external console and attaching a remote debugger.

I also ran into this problem when trying to write a simple command line application.

Another alternative to creating your own BufferedReader object from System.in is to use java.util.Scanner like this:

import java.util.Scanner;

Scanner in;
in = new Scanner(System.in);

String s = in.nextLine();

Of course this will not be a drop-in replacement to Console, but will give you access to a variety of different input functions.

Here's more documentation on Scanner from Oracle.

According to the API:

"If the virtual machine is started from an interactive command line without redirecting the standard input and output streams then its console will exist and will typically be connected to the keyboard and display from which the virtual machine was launched. If the virtual machine is started automatically, for example by a background job scheduler, then it will typically not have a console."

System.console() returns null

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