Problem with String introduction-read

[czarny020]

import java.io.*; // brakuje ci tego wiersza
import java.util.Scanner;

public class Main
  {
    public static void main(String args[])
    {
        //z wyświetleniem podpowiedzi
        Console con=System.console();
        String txt=con.readLine("Napisz cokolwiek a potem naciśnij ENTER ");
        System.out.println(txt);
        //z wyświetleniem podpowiedzi i rozbiciem na słowa
        System.out.println("Napisz cokolwiek a potem naciśnij Ctrl-C");
        Scanner sc=new Scanner(System.in);
        while(sc.hasNext())
        {
            String xtx=sc.next();
            System.out.println(xtx);
        }
    }
}

reply:

Exception in thread "main" java.lang.NullPointerException
        at Main.main(Main.java:10)

What the problem?

[doWhile]

Read the API for the classes and methods you are using, some of which may return null. For instance:
System.console() - "returns The system console, if any, otherwise null. "

[Eranga]

Exception in thread "main" java.lang.NullPointerException
        at Main.main(Main.java:10)

What the problem?

Check what you are doing on line 10 of Main.java. And read the API about the error.

One more thing, even it's not an error (actually some of the advanced IDEs not allowed that) don't use Mainas a class name. main is used to named the main method in a Java class and may unclear when you are reading next time. It's a good practice not to do such things when you are coding. :)