Made each "basic" listeners register themselves on instanciation

src/main/java/world/bentobox/bentobox/BentoBox.java

@@ -5,7 +5,6 @@ import java.util.Optional;
 import org.apache.commons.lang.exception.ExceptionUtils;
 import org.bukkit.Bukkit;
 import org.bukkit.generator.ChunkGenerator;
-import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.java.JavaPlugin;
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
@@ -199,24 +198,29 @@ public class BentoBox extends JavaPlugin {
      * Registers listeners.
      */
     private void registerListeners() {
-        PluginManager manager = getServer().getPluginManager();
+        // Player join/leave events
-        // Player join events
+        new JoinLeaveListener(this);
-        manager.registerEvents(new JoinLeaveListener(this), this);
+
         // Panel listener manager
-        manager.registerEvents(new PanelListenerManager(), this);
+        new PanelListenerManager(this);
+
         // Nether portals
-        manager.registerEvents(new NetherPortals(this), this);
+        new NetherPortals(this);
+
         // Nether trees conversion
-        manager.registerEvents(new NetherTreesListener(this), this);
+        new NetherTreesListener(this);
+
         // End dragon blocking
-        manager.registerEvents(new BlockEndDragon(this), this);
+        new BlockEndDragon(this);
+
         // Banned visitor commands
-        manager.registerEvents(new BannedVisitorCommands(this), this);
+        new BannedVisitorCommands(this);
+
         // Death counter
-        manager.registerEvents(new DeathListener(this), this);
+        new DeathListener(this);
-        // Island Delete Manager
+
+        // Island Deletion Manager
         islandDeletionManager = new IslandDeletionManager(this);
-        manager.registerEvents(islandDeletionManager, this);
     }
 
     @Override

src/main/java/world/bentobox/bentobox/listeners/BannedVisitorCommands.java

@@ -5,6 +5,7 @@ import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
 import org.bukkit.event.player.PlayerCommandPreprocessEvent;
 
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.localization.TextVariables;
 import world.bentobox.bentobox.api.user.User;
@@ -21,8 +22,9 @@ public class BannedVisitorCommands implements Listener {
     /**
      * @param plugin - plugin
      */
-    public BannedVisitorCommands(BentoBox plugin) {
+    public BannedVisitorCommands(@NonNull BentoBox plugin) {
         this.plugin = plugin;
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
     }
 
     /**

src/main/java/world/bentobox/bentobox/listeners/BlockEndDragon.java

@@ -9,16 +9,17 @@ import org.bukkit.event.block.BlockBreakEvent;
 import org.bukkit.event.block.BlockPlaceEvent;
 import org.bukkit.event.world.ChunkLoadEvent;
 
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.lists.Flags;
 
-
 public class BlockEndDragon implements Listener {
 
     private BentoBox plugin;
 
-    public BlockEndDragon(BentoBox plugin) {
+    public BlockEndDragon(@NonNull BentoBox plugin) {
         this.plugin = plugin;
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
     }
 
     /**

src/main/java/world/bentobox/bentobox/listeners/DeathListener.java

@@ -5,6 +5,7 @@ import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
 import org.bukkit.event.entity.PlayerDeathEvent;
 
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 
 /**
@@ -16,9 +17,9 @@ public class DeathListener implements Listener {
 
     private BentoBox plugin;
 
-    public DeathListener(BentoBox plugin) {
+    public DeathListener(@NonNull BentoBox plugin) {
-        super();
         this.plugin = plugin;
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
     }
 
     @EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)

src/main/java/world/bentobox/bentobox/listeners/JoinLeaveListener.java

@@ -12,6 +12,7 @@ import org.bukkit.event.Listener;
 import org.bukkit.event.player.PlayerJoinEvent;
 import org.bukkit.event.player.PlayerQuitEvent;
 
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.localization.TextVariables;
 import world.bentobox.bentobox.api.user.User;
@@ -29,9 +30,10 @@ public class JoinLeaveListener implements Listener {
     /**
      * @param plugin - plugin object
      */
-    public JoinLeaveListener(BentoBox plugin) {
+    public JoinLeaveListener(@NonNull BentoBox plugin) {
         this.plugin = plugin;
-        players = plugin.getPlayers();
+        this.players = plugin.getPlayers();
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
     }
 
     @EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)

src/main/java/world/bentobox/bentobox/listeners/NetherPortals.java

@@ -1,11 +1,8 @@
 package world.bentobox.bentobox.listeners;
 
 import org.bukkit.Location;
-import org.bukkit.Material;
-import org.bukkit.Tag;
 import org.bukkit.World;
 import org.bukkit.World.Environment;
-import org.bukkit.block.BlockState;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
@@ -18,9 +15,9 @@ import org.bukkit.event.entity.EntityPortalEvent;
 import org.bukkit.event.player.PlayerBucketEmptyEvent;
 import org.bukkit.event.player.PlayerPortalEvent;
 import org.bukkit.event.player.PlayerTeleportEvent.TeleportCause;
-import org.bukkit.event.world.StructureGrowEvent;
 import org.bukkit.util.Vector;
 
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.localization.TextVariables;
 import world.bentobox.bentobox.api.user.User;
@@ -32,8 +29,9 @@ public class NetherPortals implements Listener {
     private static final String SPAWN_PROTECTED = "protection.spawn-protected";
     private final BentoBox plugin;
 
-    public NetherPortals(BentoBox plugin) {
+    public NetherPortals(@NonNull BentoBox plugin) {
         this.plugin = plugin;
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
     }
 
     /**

src/main/java/world/bentobox/bentobox/listeners/PanelListenerManager.java

@@ -13,6 +13,7 @@ import org.bukkit.event.inventory.InventoryType.SlotType;
 import org.bukkit.event.player.PlayerQuitEvent;
 import org.bukkit.inventory.Inventory;
 
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.panels.Panel;
 import world.bentobox.bentobox.api.panels.PanelItem;
@@ -22,6 +23,13 @@ public class PanelListenerManager implements Listener {
 
     private static HashMap<UUID, Panel> openPanels = new HashMap<>();
 
+    private BentoBox plugin;
+
+    public PanelListenerManager(@NonNull BentoBox plugin) {
+        this.plugin = plugin;
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
+    }
+
     @EventHandler(priority = EventPriority.LOWEST)
     public void onInventoryClick(InventoryClickEvent event) {
         User user = User.getInstance(event.getWhoClicked()); // The player that clicked the item
@@ -31,7 +39,7 @@ public class PanelListenerManager implements Listener {
             // Check the name of the panel
             if (inventory.getName().equals(openPanels.get(user.getUniqueId()).getInventory().getName())) {
                 // Close inventory if clicked outside and if setting is true
-                if (BentoBox.getInstance().getSettings().isClosePanelOnClickOutside() && event.getSlotType().equals(SlotType.OUTSIDE)) {
+                if (plugin.getSettings().isClosePanelOnClickOutside() && event.getSlotType().equals(SlotType.OUTSIDE)) {
                     event.getWhoClicked().closeInventory();
                     return;
                 }

src/main/java/world/bentobox/bentobox/listeners/flags/NetherTreesListener.java

@@ -8,6 +8,7 @@ import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
 import org.bukkit.event.world.StructureGrowEvent;
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.configuration.WorldSettings;
 
@@ -20,8 +21,9 @@ public class NetherTreesListener implements Listener {
 
     private BentoBox plugin;
 
-    public NetherTreesListener(BentoBox plugin) {
+    public NetherTreesListener(@NonNull BentoBox plugin) {
         this.plugin = plugin;
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
     }
 
     /**

src/main/java/world/bentobox/bentobox/managers/IslandDeletionManager.java

@@ -9,6 +9,7 @@ import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
 
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.events.BentoBoxReadyEvent;
 import world.bentobox.bentobox.api.events.island.IslandEvent.IslandDeleteChunksEvent;
@@ -32,8 +33,9 @@ public class IslandDeletionManager implements Listener {
     private Database<IslandDeletion> handler;
     private Set<Location> inDeletion;
 
-    public IslandDeletionManager(BentoBox plugin) {
+    public IslandDeletionManager(@NonNull BentoBox plugin) {
         this.plugin = plugin;
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
         handler = new Database<>(plugin, IslandDeletion.class);
         inDeletion = new HashSet<>();
     }