How do I merge and sort the 2 lists in numerical order?

//Program05.java
//Mac Howard

import java.util.Scanner;

public class Program05 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner input = new Scanner(System.in);
		
		//Variables
		int[] list1;
		int[] list2;		
				
		//Input lists
		System.out.print("Enter list 1 (the first integer entered determines size of the list): ");
		int size1 = input.nextInt();
		list1 = new int[size1];
		for(int i = 0; i < list1.length; i++) {
			list1[i] = input.nextInt();
		}
		System.out.print("Enter list 2 (the first integer entered determines size of the list): ");
		int size2 = input.nextInt();
		list2 = new int[size2];
		for(int i = 0; i < list2.length; i++) {
			list2[i] = input.nextInt();
		}
		//Delete this
		for (int i = 0; i < list1.length; i++) {
			System.out.print( list1[i] + " ");
		}
		for (int i = 0; i < list2.length; i++) {
			System.out.print( list2[i] + " ");
		}
	}
	
	public static int[] merge(int[] list1, int[] list2) {
		
	}

}