Return if the proxy is disabling

bungeecord/src/main/java/me/william278/husksync/HuskSyncBungeeCord.java

@@ -31,6 +31,7 @@ public final class HuskSyncBungeeCord extends Plugin {
     private static final int METRICS_ID = 13141;
 
     private static HuskSyncBungeeCord instance;
+
     public static HuskSyncBungeeCord getInstance() {
         return instance;
     }
@@ -38,12 +39,16 @@ public final class HuskSyncBungeeCord extends Plugin {
     // Whether the plugin is ready to accept redis messages
     public static boolean readyForRedis = false;
 
+    // Whether the plugin is in the process of disabling and should skip responding to handshake confirmations
+    public static boolean isDisabling = false;
+
     /**
-     Set of all the {@link Server}s that have completed the synchronisation handshake with HuskSync on the proxy
+     * Set of all the {@link Server}s that have completed the synchronisation handshake with HuskSync on the proxy
      */
     public static HashSet<Server> synchronisedServers;
 
     private static HashMap<String, Database> clusterDatabases;
+
     public static Connection getConnection(String clusterId) throws SQLException {
         return clusterDatabases.get(clusterId).getConnection();
     }
@@ -78,6 +83,7 @@ public final class HuskSyncBungeeCord extends Plugin {
         }
 
         // Initialize the database
+        clusterDatabases = new HashMap<>();
         for (Settings.SynchronisationCluster cluster : Settings.clusters) {
             Database clusterDatabase = switch (Settings.dataStorageType) {
                 case SQLITE -> new SQLite(this, cluster);
@@ -134,6 +140,7 @@ public final class HuskSyncBungeeCord extends Plugin {
     @Override
     public void onDisable() {
         // Plugin shutdown logic
+        isDisabling = true;
 
         // Send terminating handshake message
         for (Server server : synchronisedServers) {
@@ -159,5 +166,7 @@ public final class HuskSyncBungeeCord extends Plugin {
     /**
      * A record representing a server synchronised on the network and whether it has MySqlPlayerDataBridge installed
      */
-    public record Server(UUID serverUUID, boolean hasMySqlPlayerDataBridge, String huskSyncVersion, String serverBrand, String clusterId) { }
+    public record Server(UUID serverUUID, boolean hasMySqlPlayerDataBridge, String huskSyncVersion, String serverBrand,
+                         String clusterId) {
+    }
 }

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

@@ -131,6 +131,7 @@ public class BungeeRedisListener extends RedisListener {
             }
             case CONNECTION_HANDSHAKE -> {
                 // Reply to a Bukkit server's connection handshake to complete the process
+                if (HuskSyncBungeeCord.isDisabling) return; // Return if the Proxy is disabling
                 final UUID serverUUID = UUID.fromString(message.getMessageDataElements()[0]);
                 final boolean hasMySqlPlayerDataBridge = Boolean.parseBoolean(message.getMessageDataElements()[1]);
                 final String bukkitBrand = message.getMessageDataElements()[2];