Update to use Collections.emptyMap()

src/de/steamwar/sql/UserElo.java

@@ -25,10 +25,7 @@ import de.steamwar.sql.internal.Statement;
 import de.steamwar.sql.internal.Table;
 import lombok.AllArgsConstructor;
 
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 
 @AllArgsConstructor
@@ -83,7 +80,7 @@ public class UserElo {
         int newPlacement = getPlacement(elo, gameMode);
 
         if (oldPlacement <= 3 || newPlacement <= 3) {
-            gameModeUserEloCache.getOrDefault(gameMode, new HashMap<>()).remove(userId);
+            gameModeUserEloCache.getOrDefault(gameMode, Collections.emptyMap()).remove(userId);
             emblemCache.clear();
         }