How to Stop Accepting User Input Once Array is Filled in Java

Question

Let me start by saying, this is NOT a homework question. I am not satisfied with the pace of my JAVA class, so I'm branching out and making personal programs that I would benefit from using. I copy and pasted a program to sort integers into descending order and modified it so it would sort doubles in ascending form to help with homework in my Stats class. (Yes, I know there are sorters on the web, just trying to develop my programming skills.) My question is how do I modify my program so that when the user has filled the array, the program automatically sorts the numbers without the user hitting "Enter" or using a loop to check for -1 or 0? This program satisfies my needs, but I'm thinking in terms of real world users. I tried searching for the answer, but maybe I'm not wording my question right. I hope I described my issue accurately, let me know if you have any suggestions, thank you.

Here's my code.

package sort_numbers_in_ascending_order;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("How Many Numbers Do You Want to Sort? ");
        int size  = input.nextInt();
        double[] newArr = new double [size];
        System.out.print("Enter " + size + " Numbers to Sort: ");

        for(int input_array = 0; input_array<size; input_array++) {
        //assigns values to array.
            newArr[input_array] = (double)input.nextDouble();
        }

        for(int enter_number = 0; enter_number < size; enter_number++) {
        //init. enter_number to 1,                                                                   
            // while enter_number is less than size
            for(int sort_num = 1; sort_num < size; sort_num++) {       
            // of array, processes through loops, increments
                //for loop sorts each index in array by processing 
                //each index through if loop.   
                if (newArr[sort_num] < newArr[sort_num-1]) { 
                //if an index is less than its neighbor on 
                    //r.h.s, swap values in indexes.
                    double swapNum = (double)newArr[sort_num];
                    newArr[sort_num] = newArr[sort_num-1];
                    newArr[sort_num-1] = swapNum;
                }
            }
        }
        System.out.println("Here are the Sorted Numbers: ");

        for (int printNum=0; printNum<size; printNum++) {
            System.out.print(newArr[printNum] + " ");//prints each index
        }
        System.out.println();
    }
}

Answer 1

They have to hit the enter key at least once to enter the input.

1. Maybe just have them enter the numbers to sort, and not initially say how many. This would require you to dynamically grow a List of numbers instead of a fixed sized array.

2. I know you are learning, but sorting the array like you are has terrible performance, if this isn't for homework, the best way to sort is by using Collections.sort()