A file chosen by the user

A program is more useful when the user can pick the file. It then needs two Scanners: one for the keyboard and one for the file, each with a name of its own:

apples
bread
coffee

import java.nio.file.Paths;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Which file?");
        String fileName = scanner.nextLine();

        try (Scanner fileScanner = new Scanner(Paths.get(fileName))) {
            while (fileScanner.hasNextLine()) {
                System.out.println(fileScanner.nextLine());
            }
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

shopping.txt

Which file?
apples
bread
coffee

• scanner reads the keyboard, and fileScanner reads the file. Mixing them up is an easy slip: scanner.nextLine() inside the loop would read the keyboard, not the file.
• Paths.get(fileName) takes any String, here the name the user typed.
• A name that doesn't exist, such as shoping.txt, ends up in the catch block, and the program prints Error: shoping.txt.
• The keyboard Scanner isn't put in a try (...). Closing it would close the keyboard input as well, and nothing more could be read from it.