Java InputMismatchException

❮ Errors & Exceptions

import java.util.InputMismatchException;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner myObj = new Scanner("Hello");
    try {
      int myNum = myObj.nextInt();
      System.out.println(myNum);
    } catch (InputMismatchException e) {
      System.out.println("Error: please enter a whole number.");
    }
  }
}

Definition and Usage

An InputMismatchException happens when a Scanner reads a value of the wrong type, for example when nextInt() finds text instead of a whole number.

It usually happens when the user types something unexpected. In the example, the Scanner reads from the text "Hello" instead of the keyboard, so the result is always the same.

Tip: Use hasNextInt() to check if the next value is a whole number, before you read it.

Related Pages

Java Exceptions (try...catch) Tutorial

Java Errors Tutorial