java int olup olmadığını kontrol

public static void main (String[]args)
  {
    Scanner scan = new Scanner (System.in);
    int a;
    if (scan.hasNextInt ())
      {
	    a = scan.nextInt ();
      }
    else
      {
        //oops
      }
  }

            Scanner scan = new Scanner (System.in);
            int a;
            System.out.println("Please enter a number: ");
            while(!scan.hasNextInt()){
                System.out.println("Please enter only integer value.");
                scan.nextLine();
            }
            a = scan.nextInt ();
            System.out.println(a);