Two dimensional array as buffer for screen Java Exercise - Java Programming Course

import java.util.*;
public class Main
{
	public static void main(String[] args)
	{
		char[][] position = new char[20][70];

		Random generator = new Random();
		int i = 0;

		for (; i < 80; i++)
		{
			position[generator.nextInt(20)][generator.nextInt(70)] = 'X';
		}

		for (i = 0; i < 20; i++)
		{
			for (int j = 0; j < 70; j++)
			{
				System.out.print(position[i][j]);
			}

			System.out.println();
		}
	}
}