How to solve the problem "Exception in thread "main" java.io.IOException: Stream closed" for readline()?

Question

This is my own code. And it has a problem. This code works for the "exit" case without any exception, but not for the "countdown" case. I need some help to solve this problem. I use IDEA with java 15.

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoField;
import java.util.Date;
import java.util.Scanner;
import java.time.LocalTime;
import java.util.NoSuchElementException;


class Clock {
public static void run(long time) {
    for (long seconds = time; seconds >= 0; seconds--) {
        try {
            Thread.sleep(1000);
            System.out.println(seconds);
        } catch (InterruptedException exc) {
            System.out.println("Thread interrupted.");
        }
    }
    System.out.println("Done!");
}

public static int getTime() {
    int time = 0;
    System.out.print("Enter seconds: ");
    try (Scanner scan = new Scanner(System.in)) {
        time = scan.nextInt();
    } catch (NoSuchElementException exc) {
        System.out.println("NumberFormatException: " + exc);
    }
    return time;
}

public static void main(String args[]) throws Exception {
    BufferedReader scan = new BufferedReader(new InputStreamReader(System.in));
    for (; ;) {
        System.out.println("What type of alarm will you choose? 1 - countdown, 2 - particular time, 3 - exit: ");
        String action = scan.readLine();
            switch (action) {
                case "countdown":
                    long time = 0;
                    if (args.length == 1) {
                        time = Integer.parseInt(args[0]);
                    } else {
                        time = getTime();
                    }
                    run(time);
                break;

                case "exit":
                    System.out.println("Bye bye!");
                    System.exit(0);
                break;

            }
        }
    }
}

I got this exception after the compilation of my code (above): Exception in thread "main" java.io.IOException: Stream closed

question from:https://stackoverflow.com/questions/65883638/how-to-solve-the-problem-exception-in-thread-main-java-io-ioexception-stream

Answer 1

Don’t close a scanner (especially over System.in), since it also closes the underlying stream.

The code try (Scanner scan = new Scanner(System.in)) auto-closes the scanner at the end of the scope.