Fix for a ConcurrentModificationException that can occur during the data save process

bungeecord/src/main/java/me/william278/husksync/bungeecord/listener/BungeeRedisListener.java

@@ -172,7 +172,7 @@ public class BungeeRedisListener extends RedisListener {
 
                 // When all the data has been received, save it
                 if (MPDBMigrator.migratedDataSent == MPDBMigrator.playersMigrated) {
-                    MPDBMigrator.loadIncomingData();
+                    MPDBMigrator.loadIncomingData(MPDBMigrator.incomingPlayerData);
                 }
             }
         }

bungeecord/src/main/java/me/william278/husksync/bungeecord/migrator/MPDBMigrator.java

@@ -198,15 +198,17 @@ public class MPDBMigrator {
     }
 
     /**
-     * Load all incoming decoded MPDB data to cache / SQL
+     * Loads all incoming decoded MPDB data to the cache and database
+     *
+     * @param dataToLoad HashMap of the {@link PlayerData} to player Usernames that will be loaded
      */
-    public static void loadIncomingData() {
+    public static void loadIncomingData(HashMap<PlayerData, String> dataToLoad) {
         ProxyServer.getInstance().getScheduler().runAsync(plugin, () -> {
             int playersSaved = 0;
             plugin.getLogger().log(Level.INFO, "Saving data for " + playersMigrated + " players...");
 
-            for (PlayerData playerData : incomingPlayerData.keySet()) {
+            for (PlayerData playerData : dataToLoad.keySet()) {
-                String playerName = incomingPlayerData.get(playerData);
+                String playerName = dataToLoad.get(playerData);
 
                 // Add the player to the MySQL table
                 DataManager.ensurePlayerExists(playerData.getPlayerUUID(), playerName);