Read password from console in Kotlin

Question

In Java the System static method console() returns the object allowing to read from terminal. The Console instance returned by that method provides method readLine() and readPassword(). First one echoing input to the console, but second -- doesn't.

In KotlinJVM application provides top level function readLine() to read input from the console, but there is no one to readPassword(). Also the System.console() returns null.

How I can read password (without echoing) from KotlinJVM application?

I just tried these and got NPE

package com.helpchoice.kotlin.fuel.dsl

fun main(args: Array<String>) {
    try {
        System.console().readPassword("pw:")
    } catch (e: Throwable) {
        println(e::class.java.name)
    }
}

Why System.console() returns null: https://stackoverflow.com/q/4203646/869184 — Ilya, Jun 06 '18 at 04:59

score 3 · Answer 1 · answered Jun 06 '18 at 17:20

Apparently this is an IDE problem (see System.console() returns null).

So the only solution recommended: read from System.in if there is no console.

val pw = System.console()?.readPassword() ?: readLine()

This will show your password while debugging from IDE, but will hide if started from console.

score -4 · Answer 2 · answered Jun 05 '18 at 22:03

-4

Maybe you can start with creating this:

val console : Console? = System.console()
val password = console.readPassword("Enter password")

Worked for me

answered Jun 05 '18 at 22:03

Rick Mkl

1
4

Added to the question – C.A.B. Jun 06 '18 at 02:38
Had to downvote as neither this doesn't even compile nor it solves the problem – Maroš Šeleng Jun 06 '18 at 09:06

Read password from console in Kotlin

2 Answers2

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