correct update player list

core/src/main/java/mc/core/PlayerManager.java

@@ -6,6 +6,7 @@ package mc.core;
 
 import mc.core.network.NetChannel;
 
+import java.util.List;
 import java.util.Optional;
 
 public interface PlayerManager {
@@ -13,5 +14,6 @@ public interface PlayerManager {
     void joinServer(Player player);
     void leftServer(Player player);
     Optional<Player> getPlayer(String name);
+    List<Player> getPlayers();
     NetChannel getBroadcastChannel();
 }

core/src/main/java/mc/core/embedded/InMemoryPlayerManager.java

@@ -14,6 +14,7 @@ import mc.core.network.NetChannel;
 import org.springframework.beans.factory.annotation.Autowired;
 
 import java.util.*;
+import java.util.stream.Collectors;
 
 @Slf4j
 public class InMemoryPlayerManager implements PlayerManager, Runnable {
@@ -60,6 +61,11 @@ public class InMemoryPlayerManager implements PlayerManager, Runnable {
                 .findFirst();
     }
 
+    @Override
+    public List<Player> getPlayers() {
+        return players.stream().filter(Player::isOnline).collect(Collectors.toList());
+    }
+
     @Override
     public NetChannel getBroadcastChannel() {
         return new BroadcastNetChannel(players.stream().filter(Player::isOnline));