RST Challenge 6/49

import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;
import java.util.concurrent.TimeUnit;

public class Lottery {

    private static Random randomGenerator = new Random();
    private static ArrayList<Integer> numbers = new ArrayList<>();
    private static ArrayList<Integer> winningNumbers = new ArrayList<>();
    private static ArrayList<Integer> tryingNumbers = new ArrayList<>();

    private static long sixNumbersWinners   = 0;
    private static long fiveNumbersWinners  = 0;
    private static long fourNumbersWinners  = 0;
    private static long threeNumbersWinners = 0;
    private static long tickets;

    static long startProcessingTime;
    static long endProcessingTime;
    static long timeElapsed;

    public static void main(String[] args) {

        startProcessingTime = System.currentTimeMillis();
        startLottery();
        tickets = 1 * 1000 * 1000 *1000;
        playLottery(tickets);
        endProcessingTime =  System.currentTimeMillis();

        timeElapsed = endProcessingTime - startProcessingTime;

        String time  = String.format("%d min, %d sec",
                TimeUnit.MILLISECONDS.toMinutes(timeElapsed),
                TimeUnit.MILLISECONDS.toSeconds(timeElapsed) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(timeElapsed))
        );
        System.out.println("Time Ellapsed: " + time);

        displayLotteryResults();
    }

    private static void displayLotteryResults(){
        System.out.print("Winning Numbers: ");
        for (int i: winningNumbers){
            System.out.print(i + " ");
        }
        System.out.println();
        System.out.println("Tickets : "+tickets);

        System.out.println();
        System.out.println("6 No. Winners : " + sixNumbersWinners);
        System.out.println("5 No. Winners : " + fiveNumbersWinners);
        System.out.println("4 No. Winners : " + fourNumbersWinners);
        System.out.println("3 No. Winners : " + threeNumbersWinners);
    }

    private static void startLottery() {
        fillNumbers();
        selectWinningTicket();
    }

    private static void playLottery(long tickets) {
        for (int i = 1; i <= tickets; i++) {
            fillNumbers();
            selectTryingTiket();
            checkFortune();
        }
    }

    private static void checkFortune() {
        if (winningNumbers.size() == tryingNumbers.size()
                && tryingNumbers.size() == 6) {

            int k = 0;
            for (int i = 0; i < winningNumbers.size(); i++) {
                for (int j=0;j< tryingNumbers.size(); j++){
                    if (winningNumbers.get(i) == tryingNumbers.get(j)){
                        k++;
                    }
                }
            }
            switch (k) {
            case 6:
                sixNumbersWinners++;
            case 5:
                fiveNumbersWinners++;
                break;
            case 4:
                fourNumbersWinners++;
                break;
            case 3:
                threeNumbersWinners++;
                break;
            }
        }
    }

    private static void fillNumbers() {
        tryingNumbers.clear();
        numbers.clear();
        for (int i = 1; i <= 49; i++)
            numbers.add(i);
    }

    private static void selectWinningTicket() {
        for (int i = 0; i < 6; i++) {
            Collections.shuffle(numbers);
            int randomIndex = randomGenerator.nextInt(numbers.size());
            int aWinningNumber = numbers.get(randomIndex);
            winningNumbers.add(aWinningNumber);
            numbers.remove(numbers.get(randomIndex));
        }
    }

    private static void selectTryingTiket() {
        for (int i = 0; i < 6; i++) {
            Collections.shuffle(numbers);
            int randomIndex = randomGenerator.nextInt(numbers.size());
            int aWinningNumber = numbers.get(randomIndex);
            tryingNumbers.add(aWinningNumber);
            numbers.remove(numbers.get(randomIndex));
        }
    }
}