Solution: Multi-Player Game Lobby

import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
public class GameLobby {
    static class Player implements Runnable {
        private final String name;
        private final CyclicBarrier barrier;
        public Player(String name, CyclicBarrier barrier) {
            this.name = name;
            this.barrier = barrier;
        }
        @Override
        public void run() {
            try {
                System.out.println(name + " is joining...");
                
                // Simulate varying connection speeds (500ms to 2000ms)
                long delay = (long)(Math.random() * 1500) + 500;
                Thread.sleep(delay);
                System.out.println(name + " is waiting in the lobby...");
                // 3. Wait for all 4 players to reach this point
                barrier.await();
                // 4. Proceed together
                System.out.println(name + " has entered the match!");
            } catch (InterruptedException | BrokenBarrierException e) {
                e.printStackTrace();
            }
        }
    }
    public static void main(String[] args) {
        int totalPlayers = 4;
        System.out.println("Lobby is open. Waiting for " + totalPlayers + " players...");
        // 1. Create the barrier with a barrier action
        CyclicBarrier barrier = new CyclicBarrier(totalPlayers, () -> {
            System.out.println("\n*** All players are present! Game starting now! ***\n");
        });
        // 2. Start the player threads
        for (int i = 1; i <= totalPlayers; i++) {
            new Thread(new Player("Player " + i, barrier)).start();
        }
    }
}