System.console () provides NullPointerException in NetBeans

I am completely new to Java.

I have the following problem: method readLine()

or nextLine()

, nextInt()

etc. throws an exception: NullPointerException

.

I am using NetBeans IDE (if it matters).

public static void Reading()
{

    String qq;
    qq = System.console().readLine();
    System.console().printf(qq);
}

      

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2 answers


Some IDEs do not provide a console. Note what System.console()

returns null

in these cases.

From the doc

Return:

      The system console, if present, is zero otherwise.



You can always use System.in

and System.out

, namely:

String qq;
Scanner scanner = new Scanner(System.in);
qq = scanner.nextLine();
System.out.println(qq);

      

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Two things:

  • The standard way to print things is System.out.println("Thing to print");

  • The standard way to read input from the console is: Scanner s = new Scanner(System.in); String input = s.nextLine();

So, with that in mind, your code should be



public static void Reading() {
    String qq;
    Scanner s = new Scanner(System.in);
    qq = s.nextLine();
    System.out.println(qq);
    s.close();
}

      

or

public static void Reading() {
    String qq;
    try (Scanner s = new Scanner(System.in)) {
        qq = s.nextLine();
        System.out.println(qq);
    }
}

      

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