Java Program not taking the Piped input

Question

I have to work with a Java program which takes 2 user inputs like this:

Enter username:
Enter password:

So I thought of sending it like

echo -e "myusername\npassword" | java javaprogram

and

java javaprogram < input.txt

Both didn't work.

When I execute this command it's showing the error like this:

Enter userID: Enter password: Exception in thread "main" java.io.IOException: Unable to mask input in console. at..

I don't know the source code of this jar file.

What can be the reason for this ?

@Srivignesh It's prompting for user input and not taking the command line arguments — Prajwal
– Prajwal, Commented Apr 6, 2018 at 12:29
jd-gui tool is a lightweight decompiler which will help in viewing the source code — Srivignesh
– Srivignesh, Commented Apr 6, 2018 at 12:31
"myusername\npassword\n" a newline on last line? Though that error is something else... — Joop Eggen
– Joop Eggen, Commented Apr 6, 2018 at 12:39

Tripp Kinetics · Accepted Answer · 2018-04-06 12:32:34Z

3

It's very possible that the program isn't reading the password from standard input, but from the terminal. There is a program called expect, which is basically a language for scripting interactions with terminal programs.

Take a look at http://expect.sourceforge.net/

answered Apr 6, 2018 at 12:32

Tripp Kinetics

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acoelhosantos · Accepted Answer · 2018-04-06 12:34:49Z

2

Have a look at expect which helps with programmed dialogue with interactive programs. Additionally, in case you want to know more about the source of the *.jar file you are using, you can decompile it.

answered Apr 6, 2018 at 12:34

acoelhosantos

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