import java.util.Scanner;

class Example1 {
  Scanner s;
  
  public Example1() {
    // create a new scanner that reads from the keyboard
    s = new Scanner(System.in);
  }
  
  public int promptUserForNum() {
    // while we don't have an integer, ask the user to give us one
    while(true) {
      // prompt the user
      System.out.print("Please enter a number: ");
      
      try {
        // use Scanner to read the input;
        // might throw an exception!
        int x = s.nextInt();
        
        // we got a valid number; break out of this loop and return it
        return x;
      } catch (Exception e) {
        System.out.println("Not an integer!  Try again!");
        
        // we have to 'clear' the Scanner; we do this by
        // reading whatever string it was given, then
        // discard that string.
        s.next();
      }
    }
    
    // program never reaches this point
  }
  
  public static void main(String[] args) {
    // initialize our class, which has a Scanner in it
    Example1 e = new Example1();
    
    // read number
    int num = e.promptUserForNum();
    
    // tell the user what we got
    System.out.println("We got: " + num);
  }
}