What is java.util.NoSuchElementException and how do i fix it?

Question

I was trying to program a game of battleship and i ran into this error at the point where the user was prompted to enter their guess coordinates:

Exception in thread "main" java.util.NoSuchElementException


    at java.util.Scanner.throwFor(Unknown Source)
        at java.util.Scanner.next(Unknown Source)
        at java.util.Scanner.nextInt(Unknown Source)
        at java.util.Scanner.nextInt(Unknown Source)
        at game.User.takeTurn(User.java:121)
        at game.Game.main(Game.java:61)

Here is the method User.takeTurn() where the error occured:

    static void takeTurn() {
           System.out.println("Yout turn!");
           System.out.println("Enter your x guess:");
           Scanner scanInput = new Scanner(System.in);
           int x;
           x = scanInput.nextInt();
           System.out.println("You entered "+ x + ", Now enter your y     coord:");
           int y;
           y = scanInput.nextInt();
           System.out.println("You entered + " + y);
           if(Board.aiBoard[x][y] == 2) {
               System.out.println("Hit! You got a hit at: " + x + "," + y);
               Board.enemyBoardDisplay[x][y] = 'h';
               Board.aiBoard[x][y] = 3;
           }
           else {
            System.out.println("Miss!");
            Board.enemyBoardDisplay[x][y] = 'x';
            Board.aiBoard[x][y] = 1;
          }

           scanInput.close();
      }

Im not really sure if it matters or not but i also use another scanner earlier in the class. If you need more code to help just let me know. Thanks!

edit 1: Ok, even after I do scanInput.hasNextInt() its not working. I also put in an else statement that gave x a value but now x always has the value that the else statement gives. It dosent even ask for an input it just defaults to that value. But i dont want it to go to a default i want the user to pick.

edit 2: This is where i call the code in my main stub

while (gameOn == true) {
            if (turn == 0) {
                User.takeTurn();
                Board.sunkCheck();
                if (gameOn == false)
                    break;
            }

            else if (turn == 1) {
                Computer.takeTurn();
                Board.sunkCheck();
                if (gameOn == false)
                    break;
            }

This is where i use a scanner earlier in the same class as im trying to use the scanner now:

System.out
                .println("\n Please enter the first x value for your ship  (Note, this will be the first point, from this point the \n"
                        + " ship can either go vertically downward or horizontally to the right so please choose the topmost point or leftmost \n"
                        + "point to do this. Also, the board is 10x10 but due to java array indexing the coordinates go x 0-9 y 0-9: ");
        try {
        Scanner coord = new Scanner(System.in);
        userX = coord.nextInt();
        System.out.println("You entered: " + userX);
        System.out.println("Now enter the y coordinate for this point: ");
        userY = coord.nextInt();
        System.out.println("You entered: " + userY);
        System.out
                .println("Please choose the direction of your ship. Enter v for verticle or h for horizontal(case sensitive): ");
        dir = (char) System.in.read();
        coord.close();
        }
        catch(InputMismatchException e) {
            System.out.println("Good job doof, since you tried to troll we did all the values for you!");
            userX = 3;
            userY = 3;
            dir = 'v';
        }

Answer 1

You might want to check for next element before getting it in Scanner with scanInput.hasNextInt().

---

Updated:

If you use the above Scanner coord = new Scanner(System.in); and then call the function with Scanner scanInput = new Scanner(System.in); without closing the coord Scanner, then you will be having issues.

Scanners will continue to consume the stream - this may (will) lead to unexpected side-effects.

You may want to close the first one before using another (here for more ref).

---

Update:

When you close coord.close() you are closing System.in and when you try to re-read from it, it will throw the exception.

Instead of re-opening the stream every time you need input you could create your Scanner once and just re-using it.