Java - Missing Number

/* Given an array containing all numbers from 1 to N with the exception of one print the missing
 * number to the standard output.
 * Example input: array: 5 4 1 2 - Example output: 3
 */

import java.util.*;

public class MissingNumber {
    public static final java.util.Scanner input = new java.util.Scanner(System.in);

    public static void main(String[] args) {

        int len;

        System.out.print("Length of array: ");
        len = input.nextInt();

        // Get array input and assign
        int[] array = new int[len];
        System.out.print("Enter array: ");
        for(int i = 0; i < array.length; i++) {
            array[i] = input.nextInt();
        }

        // Sort array
        array = bubble(array);

        // Compare list, print missing number when found
        for(int i = 1; i < array.length; i++) {
            if(i != array[i - 1]) {
                System.out.println("The missing number is: " + i);
                break;
            }
        }
    }

    public static int[] bubble(int[] list)
   {
      int temp;
      boolean changed = false;
      do
      {
         changed = false; // Resets to false every time
         for(int j = 0; j < list.length - 1; j++) // Minus one because if uses plus one to look at next
            if(list[j] > list[j + 1]) // If next value is higher
            {
               temp = list[j]; // Shift value into temporary spot
               list[j] = list[j + 1]; // Shift higher value into value (i)
               list[j + 1] = temp; // Shift temp into higher value (swap)
               changed = true;
            }
      } while(changed); // Stop when there's no change

      return list;
   }
}