Fix viewers mutating after submitting async packet sending

.github/ISSUE_TEMPLATE/2-feature.yml

@@ -1,16 +0,0 @@
-name: 💡 Suggestion
-description: "Suggest a new feature or an improvement."
-labels:
-  - "Enhancement"
-body:
-  - type: markdown
-    attributes:
-      value: |-
-        Please suggest changes that would benefit as many users as possible, not just specific situations. Thank you for contributing to the project.
-
-  - type: textarea
-    attributes:
-      label: "Description"
-      description: "Describe the new feature or improvement."
-    validations:
-      required: true

.github/ISSUE_TEMPLATE/3-help.yml

@@ -1,42 +0,0 @@
-name: 📝 Help request
-description: "Ask a question."
-labels:
-  - "Help"
-body:
-  - type: markdown
-    attributes:
-      value: |-
-        Please make sure you are using a recent version of the plugin.
-
-  - type: checkboxes
-    attributes:
-      label: "Confirmation"
-      description: "Please confirm to have done the following checks before opening a new issue."
-      options:
-        - label: "I have read the [documentation](https://filoghost.me/docs/holographic-displays)."
-          required: true
-        - label: "I have read the [FAQ](https://filoghost.me/docs/holographic-displays/faq)."
-          required: true
-
-  - type: textarea
-    attributes:
-      label: "Description"
-      description: "Describe your goal and what you have tried so far."
-      placeholder: "What are you trying to achieve? What have you tried so far?"
-    validations:
-      required: true
-
-  - type: input
-    attributes:
-      label: "Holographic Displays version"
-      description: "Output of the command `/version HolographicDisplays`."
-      placeholder: "HolographicDisplays version 2.4.8-SNAPSHOT-b174"
-    validations:
-      required: true
-
-  - type: textarea
-    attributes:
-      label: Additional information
-      description: |-
-        Relevant attachments such as **screenshots**, **server logs**, **configurations files** or any other additional information that might be useful.
-        Text files can also be uploaded to [Pastebin](https://pastebin.com) and shared through the generated link.

.github/ISSUE_TEMPLATE/4-documentation.yml

@@ -1,16 +0,0 @@
-name: 📚 Documentation improvement
-description: "Suggest a change or report an error to improve the official documentation."
-labels:
-  - "Documentation"
-body:
-  - type: markdown
-    attributes:
-      value: |-
-        Suggest a change or report an error to improve the official documentation. Thank you for contributing to the project.
-
-  - type: textarea
-    attributes:
-      label: "Description"
-      description: "Describe what should be improved and, if possible, _how_."
-    validations:
-      required: true

README.md

@@ -17,9 +17,9 @@ Development Builds: https://ci.codemc.io/job/filoghost/job/HolographicDisplays
 
 ```xml
 <dependency>
-    <groupId>com.gmail.filoghost.holographicdisplays</groupId>
+    <groupId>me.filoghost.holographicdisplays</groupId>
     <artifactId>holographicdisplays-api</artifactId>
-    <version>2.4.9</version>
+    <version>3.0.0</version>
     <scope>provided</scope>
 </dependency>
 ```
@@ -32,7 +32,7 @@ maven {
 ```
 
 ```groovy
-compileOnly 'com.gmail.filoghost.holographicdisplays:holographicdisplays-api:2.4.9'
+compileOnly 'me.filoghost.holographicdisplays:holographicdisplays-api:3.0.0'
 ```
 
 ## License

api/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-parent</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-api</artifactId>

checkstyle/checkstyle.xml

@@ -125,7 +125,6 @@
 
         <!-- Miscellaneous -->
         <module name="ArrayTypeStyle"/>
-        <module name="AvoidEscapedUnicodeCharacters"/>
         <module name="CommentsIndentation"/>
         <module name="Indentation">
             <property name="basicOffset" value="4"/>

common/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-parent</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-common</artifactId>

core/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-parent</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-core</artifactId>
@@ -74,16 +74,6 @@
             <artifactId>holographicdisplays-nms-v1_15_r1</artifactId>
         </dependency>
 
-        <dependency>
-            <groupId>${project.groupId}</groupId>
-            <artifactId>holographicdisplays-nms-v1_16_r1</artifactId>
-        </dependency>
-
-        <dependency>
-            <groupId>${project.groupId}</groupId>
-            <artifactId>holographicdisplays-nms-v1_16_r2</artifactId>
-        </dependency>
-
         <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>holographicdisplays-nms-v1_16_r3</artifactId>
@@ -109,6 +99,31 @@
             <artifactId>holographicdisplays-nms-v1_19_r1</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>holographicdisplays-nms-v1_19_r2</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>holographicdisplays-nms-v1_19_r3</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>holographicdisplays-nms-v1_20_r1</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>holographicdisplays-nms-v1_20_r2</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>holographicdisplays-nms-v1_20_r3</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>org.spigotmc</groupId>
             <artifactId>spigot-api</artifactId>

core/src/main/java/me/filoghost/holographicdisplays/core/CoreGlobalConfig.java

@@ -0,0 +1,13 @@
+/*
+ * Copyright (C) filoghost and contributors
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+package me.filoghost.holographicdisplays.core;
+
+public class CoreGlobalConfig {
+
+    public static double spaceBetweenLines;
+    public static int maxViewRange;
+
+}

core/src/main/java/me/filoghost/holographicdisplays/core/CorePreconditions.java

@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) filoghost and contributors
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+package me.filoghost.holographicdisplays.core;
+
+import me.filoghost.fcommons.Preconditions;
+
+public class CorePreconditions {
+
+    public static void checkMainThread() {
+        Preconditions.checkMainThread("async operation is not supported");
+    }
+
+}

core/src/main/java/me/filoghost/holographicdisplays/core/HolographicDisplaysCore.java

@@ -16,7 +16,6 @@ import me.filoghost.holographicdisplays.core.api.current.DefaultHolographicDispl
 import me.filoghost.holographicdisplays.core.api.v2.V2HologramManager;
 import me.filoghost.holographicdisplays.core.api.v2.V2HologramsAPIProvider;
 import me.filoghost.holographicdisplays.core.base.BaseHologram;
-import me.filoghost.holographicdisplays.core.base.BaseHologramLines;
 import me.filoghost.holographicdisplays.core.listener.ChunkListener;
 import me.filoghost.holographicdisplays.core.listener.LineClickListener;
 import me.filoghost.holographicdisplays.core.listener.PlayerListener;
@@ -25,6 +24,7 @@ import me.filoghost.holographicdisplays.core.placeholder.tracking.ActivePlacehol
 import me.filoghost.holographicdisplays.core.tick.TickClock;
 import me.filoghost.holographicdisplays.core.tick.TickingTask;
 import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
+import me.filoghost.holographicdisplays.core.tracking.PacketSenderExecutor;
 import me.filoghost.holographicdisplays.nms.common.NMSManager;
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
@@ -41,13 +41,15 @@ public class HolographicDisplaysCore {
         try {
             nmsManager = NMSVersion.getCurrent().createNMSManager(errorCollector);
         } catch (UnknownVersionException e) {
-            throw new PluginEnableException("Holographic Displays only supports Spigot from 1.8 to 1.18.2.");
+            throw new PluginEnableException("Holographic Displays only supports Spigot from 1.8 to 1.20.");
         } catch (OutdatedVersionException e) {
             throw new PluginEnableException("Holographic Displays only supports " + e.getMinimumSupportedVersion() + " and above.");
         } catch (Throwable t) {
             throw new PluginEnableException(t, "Couldn't initialize the NMS manager.");
         }
 
+        PacketSenderExecutor.start();
+
         PlaceholderRegistry placeholderRegistry = new PlaceholderRegistry();
         TickClock tickClock = new TickClock();
         ActivePlaceholderTracker placeholderTracker = new ActivePlaceholderTracker(placeholderRegistry, tickClock);
@@ -81,7 +83,7 @@ public class HolographicDisplaysCore {
     }
 
     public void setSpaceBetweenHologramLines(double spaceBetweenLines) {
-        BaseHologramLines.spaceBetweenLines = spaceBetweenLines;
+        CoreGlobalConfig.spaceBetweenLines = spaceBetweenLines;
         for (BaseHologram hologram : apiHologramManager.getHolograms()) {
             hologram.getLines().updatePositions();
         }
@@ -90,6 +92,10 @@ public class HolographicDisplaysCore {
         }
     }
 
+    public void setMaxViewRange(int maxViewRange) {
+        CoreGlobalConfig.maxViewRange = maxViewRange;
+    }
+
     public void disable() {
         if (lineTrackerManager != null) {
             lineTrackerManager.resetViewersAndSendDestroyPackets();
@@ -100,6 +106,8 @@ public class HolographicDisplaysCore {
                 nmsManager.uninjectPacketListener(player);
             }
         }
+
+        PacketSenderExecutor.stopGracefully();
     }
 
 }

core/src/main/java/me/filoghost/holographicdisplays/core/NMSVersion.java

@@ -32,13 +32,18 @@ public enum NMSVersion {
     /* 1.13.1 - 1.13.2 */ v1_13_R2(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_13_R2.VersionNMSManager(errorCollector)),
     /* 1.14 - 1.14.4   */ v1_14_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_14_R1.VersionNMSManager(errorCollector)),
     /* 1.15 - 1.15.2   */ v1_15_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_15_R1.VersionNMSManager(errorCollector)),
-    /* 1.16 - 1.16.1   */ v1_16_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_16_R1.VersionNMSManager(errorCollector)),
-    /* 1.16.2 - 1.16.3 */ v1_16_R2(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_16_R2.VersionNMSManager(errorCollector)),
+    /* 1.16 - 1.16.1   */ v1_16_R1(NMSManagerFactory.outdatedVersion("1.16.4")),
+    /* 1.16.2 - 1.16.3 */ v1_16_R2(NMSManagerFactory.outdatedVersion("1.16.4")),
     /* 1.16.4 - 1.16.5 */ v1_16_R3(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_16_R3.VersionNMSManager(errorCollector)),
     /* 1.17            */ v1_17_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_17_R1.VersionNMSManager(errorCollector)),
     /* 1.18 - 1.18.1   */ v1_18_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_18_R1.VersionNMSManager(errorCollector)),
     /* 1.18.2          */ v1_18_R2(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_18_R2.VersionNMSManager(errorCollector)),
-    /* 1.19 - ?        */ v1_19_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_19_R1.VersionNMSManager(errorCollector)),
+    /* 1.19 - 1.19.2   */ v1_19_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_19_R1.VersionNMSManager(errorCollector)),
+    /* 1.19.3          */ v1_19_R2(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_19_R2.VersionNMSManager(errorCollector)),
+    /* 1.19.4          */ v1_19_R3(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_19_R3.VersionNMSManager(errorCollector)),
+    /* 1.20 - 1.20.1   */ v1_20_R1(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_20_R1.VersionNMSManager(errorCollector)),
+    /* 1.20.2          */ v1_20_R2(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_20_R2.VersionNMSManager(errorCollector)),
+    /* 1.20.3 - 1.20.4 */ v1_20_R3(errorCollector -> new me.filoghost.holographicdisplays.nms.v1_20_R3.VersionNMSManager(errorCollector)),
     /* Other versions  */ UNKNOWN(NMSManagerFactory.unknownVersion());
 
     private static final NMSVersion CURRENT_VERSION = detectCurrentVersion();

core/src/main/java/me/filoghost/holographicdisplays/core/api/current/APIHologram.java

@@ -9,6 +9,7 @@ import me.filoghost.fcommons.Preconditions;
 import me.filoghost.holographicdisplays.api.Position;
 import me.filoghost.holographicdisplays.api.hologram.Hologram;
 import me.filoghost.holographicdisplays.api.hologram.PlaceholderSetting;
+import me.filoghost.holographicdisplays.core.CorePreconditions;
 import me.filoghost.holographicdisplays.core.base.BaseHologram;
 import me.filoghost.holographicdisplays.core.base.ImmutablePosition;
 import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
@@ -30,7 +31,7 @@ class APIHologram extends BaseHologram implements Hologram {
             LineTrackerManager lineTrackerManager) {
         super(position, lineTrackerManager);
         Preconditions.notNull(plugin, "plugin");
-        this.lines = new APIHologramLines(this);
+        this.lines = new APIHologramLines(this, lineTrackerManager);
         this.plugin = plugin;
         this.hologramManager = hologramManager;
         this.placeholderSetting = PlaceholderSetting.DEFAULT;
@@ -53,6 +54,7 @@ class APIHologram extends BaseHologram implements Hologram {
 
     @Override
     public void setPlaceholderSetting(@NotNull PlaceholderSetting placeholderSetting) {
+        CorePreconditions.checkMainThread();
         Preconditions.notNull(placeholderSetting, "placeholderSetting");
         checkNotDeleted();
 

core/src/main/java/me/filoghost/holographicdisplays/core/api/current/APIHologramLines.java

@@ -11,6 +11,7 @@ import me.filoghost.holographicdisplays.api.hologram.line.HologramLine;
 import me.filoghost.holographicdisplays.api.hologram.line.ItemHologramLine;
 import me.filoghost.holographicdisplays.api.hologram.line.TextHologramLine;
 import me.filoghost.holographicdisplays.core.base.BaseHologramLines;
+import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
 import org.bukkit.inventory.ItemStack;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -19,8 +20,8 @@ class APIHologramLines extends BaseHologramLines<APIHologramLine> implements Hol
 
     private final APIHologram hologram;
 
-    APIHologramLines(APIHologram hologram) {
-        super(hologram);
+    APIHologramLines(APIHologram hologram, LineTrackerManager lineTrackerManager) {
+        super(hologram, lineTrackerManager);
         this.hologram = hologram;
     }
 

core/src/main/java/me/filoghost/holographicdisplays/core/api/current/APIItemHologramLine.java

@@ -8,6 +8,7 @@ package me.filoghost.holographicdisplays.core.api.current;
 import me.filoghost.holographicdisplays.api.hologram.line.HologramLineClickListener;
 import me.filoghost.holographicdisplays.api.hologram.line.HologramLinePickupListener;
 import me.filoghost.holographicdisplays.api.hologram.line.ItemHologramLine;
+import me.filoghost.holographicdisplays.core.CorePreconditions;
 import me.filoghost.holographicdisplays.core.base.BaseItemHologramLine;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
@@ -24,35 +25,39 @@ class APIItemHologramLine extends BaseItemHologramLine implements ItemHologramLi
 
     @Override
     public @Nullable HologramLinePickupListener getPickupListener() {
+        CorePreconditions.checkMainThread();
         return pickupListener;
     }
 
     @Override
     public void setPickupListener(@Nullable HologramLinePickupListener pickupListener) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         this.pickupListener = pickupListener;
     }
 
-    @Override
-    public @Nullable HologramLineClickListener getClickListener() {
-        return clickListener;
-    }
-
     @Override
     public boolean hasPickupCallback() {
         return pickupListener != null;
     }
 
     @Override
-    protected void invokePickupCallback(Player player) {
+    protected void invokeExternalPickupCallback(Player player) {
         if (pickupListener != null) {
             pickupListener.onPickup(new SimpleHologramLinePickupEvent(player));
         }
     }
 
+    @Override
+    public @Nullable HologramLineClickListener getClickListener() {
+        CorePreconditions.checkMainThread();
+        return clickListener;
+    }
+
     @Override
     public void setClickListener(@Nullable HologramLineClickListener clickListener) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         this.clickListener = clickListener;
@@ -65,7 +70,7 @@ class APIItemHologramLine extends BaseItemHologramLine implements ItemHologramLi
     }
 
     @Override
-    protected void invokeClickCallback(Player player) {
+    protected void invokeExternalClickCallback(Player player) {
         if (clickListener != null) {
             clickListener.onClick(new SimpleHologramLineClickEvent(player));
         }

core/src/main/java/me/filoghost/holographicdisplays/core/api/current/APITextHologramLine.java

@@ -8,6 +8,7 @@ package me.filoghost.holographicdisplays.core.api.current;
 import me.filoghost.holographicdisplays.api.hologram.PlaceholderSetting;
 import me.filoghost.holographicdisplays.api.hologram.line.HologramLineClickListener;
 import me.filoghost.holographicdisplays.api.hologram.line.TextHologramLine;
+import me.filoghost.holographicdisplays.core.CorePreconditions;
 import me.filoghost.holographicdisplays.core.base.BaseTextHologramLine;
 import org.bukkit.entity.Player;
 import org.jetbrains.annotations.Nullable;
@@ -30,6 +31,7 @@ class APITextHologramLine extends BaseTextHologramLine implements TextHologramLi
 
     @Override
     public void setClickListener(@Nullable HologramLineClickListener clickListener) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         this.clickListener = clickListener;
@@ -47,7 +49,7 @@ class APITextHologramLine extends BaseTextHologramLine implements TextHologramLi
     }
 
     @Override
-    protected void invokeClickCallback(Player player) {
+    protected void invokeExternalClickCallback(Player player) {
         if (clickListener != null) {
             clickListener.onClick(new SimpleHologramLineClickEvent(player));
         }

core/src/main/java/me/filoghost/holographicdisplays/core/api/current/DefaultHolographicDisplaysAPIProvider.java

@@ -17,26 +17,20 @@ import org.bukkit.block.Block;
 import org.bukkit.entity.Entity;
 import org.bukkit.plugin.Plugin;
 
-import java.util.Map;
-import java.util.WeakHashMap;
-import java.util.function.Function;
-
 public class DefaultHolographicDisplaysAPIProvider extends HolographicDisplaysAPIProvider {
 
-    private final Map<Plugin, HolographicDisplaysAPI> apiCache;
-    private final Function<Plugin, HolographicDisplaysAPI> apiFactory;
+    private final APIHologramManager apiHologramManager;
+    private final PlaceholderRegistry placeholderRegistry;
 
     public DefaultHolographicDisplaysAPIProvider(APIHologramManager apiHologramManager, PlaceholderRegistry placeholderRegistry) {
-        this.apiCache = new WeakHashMap<>();
-        this.apiFactory = plugin -> new DefaultHolographicDisplaysAPI(plugin, apiHologramManager, placeholderRegistry);
+        this.apiHologramManager = apiHologramManager;
+        this.placeholderRegistry = placeholderRegistry;
     }
 
     @Override
     public HolographicDisplaysAPI getHolographicDisplaysAPI(Plugin plugin) {
         Preconditions.notNull(plugin, "plugin");
-
-        // Optimization: avoid creating a new instance every time a plugin requests it, in case it never stores a reference
-        return apiCache.computeIfAbsent(plugin, apiFactory);
+        return new DefaultHolographicDisplaysAPI(plugin, apiHologramManager, placeholderRegistry);
     }
 
     @Override

core/src/main/java/me/filoghost/holographicdisplays/core/api/v2/V2Hologram.java

@@ -37,7 +37,7 @@ class V2Hologram extends BaseHologram implements Hologram {
         super(position, lineTrackerManager);
         this.plugin = plugin;
         this.hologramManager = hologramManager;
-        this.lines = new BaseHologramLines<>(this);
+        this.lines = new BaseHologramLines<>(this, lineTrackerManager);
         this.visibilityManager = new V2VisibilityManager(getVisibilitySettings());
         this.creationTimestamp = System.currentTimeMillis();
     }

core/src/main/java/me/filoghost/holographicdisplays/core/api/v2/V2ItemLine.java

@@ -46,7 +46,7 @@ class V2ItemLine extends BaseItemHologramLine implements ItemLine, V2HologramLin
     }
 
     @Override
-    protected void invokeClickCallback(Player player) {
+    protected void invokeExternalClickCallback(Player player) {
         if (touchHandler != null) {
             touchHandler.onTouch(player);
         }
@@ -68,7 +68,7 @@ class V2ItemLine extends BaseItemHologramLine implements ItemLine, V2HologramLin
     }
 
     @Override
-    protected void invokePickupCallback(Player player) {
+    protected void invokeExternalPickupCallback(Player player) {
         if (pickupHandler != null) {
             pickupHandler.onPickup(player);
         }

core/src/main/java/me/filoghost/holographicdisplays/core/api/v2/V2TextLine.java

@@ -48,7 +48,7 @@ class V2TextLine extends BaseTextHologramLine implements TextLine, V2HologramLin
     }
 
     @Override
-    protected void invokeClickCallback(Player player) {
+    protected void invokeExternalClickCallback(Player player) {
         if (touchHandler != null) {
             touchHandler.onTouch(player);
         }

core/src/main/java/me/filoghost/holographicdisplays/core/base/BaseClickableHologramLine.java

@@ -6,8 +6,6 @@
 package me.filoghost.holographicdisplays.core.base;
 
 import me.filoghost.fcommons.logging.Log;
-import me.filoghost.holographicdisplays.common.PositionCoordinates;
-import org.bukkit.Location;
 import org.bukkit.entity.Player;
 
 public abstract class BaseClickableHologramLine extends BaseHologramLine {
@@ -17,30 +15,16 @@ public abstract class BaseClickableHologramLine extends BaseHologramLine {
     }
 
     public void onClick(Player player) {
-        if (hasClickCallback() && canInteract(player) && isInClickRange(player)) {
-            try {
-                invokeClickCallback(player);
-            } catch (Throwable t) {
-                Log.warning("The plugin " + getCreatorPlugin().getName() + " generated an exception"
-                        + " when the player " + player.getName() + " clicked a hologram.", t);
-            }
+        try {
+            invokeExternalClickCallback(player);
+        } catch (Throwable t) {
+            Log.warning("The plugin " + getCreatorPlugin().getName() + " generated an exception"
+                    + " when the player " + player.getName() + " clicked a hologram.", t);
         }
     }
 
     public abstract boolean hasClickCallback();
 
-    protected abstract void invokeClickCallback(Player player);
-
-    private boolean isInClickRange(Player player) {
-        Location playerLocation = player.getLocation();
-        PositionCoordinates positionCoordinates = this.getCoordinates();
-
-        double xDiff = playerLocation.getX() - positionCoordinates.getX();
-        double yDiff = playerLocation.getY() + 1.3 - positionCoordinates.getY(); // Use shoulder height
-        double zDiff = playerLocation.getZ() - positionCoordinates.getZ();
-
-        double distanceSquared = (xDiff * xDiff) + (yDiff * yDiff) + (zDiff * zDiff);
-        return distanceSquared < 5 * 5;
-    }
+    protected abstract void invokeExternalClickCallback(Player player);
 
 }

core/src/main/java/me/filoghost/holographicdisplays/core/base/BaseHologram.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.core.base;
 
 import me.filoghost.fcommons.Preconditions;
+import me.filoghost.holographicdisplays.core.CorePreconditions;
 import me.filoghost.holographicdisplays.core.api.current.DefaultVisibilitySettings;
 import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
 import org.bukkit.Chunk;
@@ -70,6 +71,7 @@ public abstract class BaseHologram extends BaseHologramComponent {
     }
 
     public void setPosition(@NotNull ImmutablePosition position) {
+        CorePreconditions.checkMainThread();
         Preconditions.notNull(position, "position");
         checkNotDeleted();
 

core/src/main/java/me/filoghost/holographicdisplays/core/base/BaseHologramLine.java

@@ -8,9 +8,6 @@ package me.filoghost.holographicdisplays.core.base;
 import me.filoghost.fcommons.Preconditions;
 import me.filoghost.holographicdisplays.common.PositionCoordinates;
 import me.filoghost.holographicdisplays.core.api.current.DefaultVisibilitySettings;
-import me.filoghost.holographicdisplays.core.tracking.LineTracker;
-import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
-import org.bukkit.GameMode;
 import org.bukkit.World;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
@@ -20,24 +17,30 @@ import org.jetbrains.annotations.Nullable;
 public abstract class BaseHologramLine extends BaseHologramComponent implements EditableHologramLine {
 
     private final BaseHologram hologram;
-    private final LineTracker<?> tracker;
 
     private PositionCoordinates coordinates;
 
+    /**
+     * Flag to indicate that the line has changed in some way and update packets might be necessary.
+     */
+    private boolean changed;
+
     protected BaseHologramLine(BaseHologram hologram) {
         Preconditions.notNull(hologram, "hologram");
         this.hologram = hologram;
-        this.tracker = createTracker(hologram.getTrackerManager());
+        setChanged(); // Force the initial refresh
     }
 
-    protected abstract LineTracker<?> createTracker(LineTrackerManager trackerManager);
+    public boolean hasChanged() {
+        return changed;
+    }
 
     public final void setChanged() {
-        tracker.setLineChanged();
+        changed = true;
     }
 
-    protected final boolean isViewer(Player player) {
-        return tracker.isViewer(player);
+    public void clearChanged() {
+        changed = false;
     }
 
     @Override
@@ -77,12 +80,4 @@ public abstract class BaseHologramLine extends BaseHologramComponent implements
         return hologram.getVisibilitySettings();
     }
 
-    protected boolean canInteract(Player player) {
-        return !isDeleted()
-                && player.isOnline()
-                && player.getGameMode() != GameMode.SPECTATOR
-                && isViewer(player)
-                && isVisibleTo(player);
-    }
-
 }

core/src/main/java/me/filoghost/holographicdisplays/core/base/BaseHologramLines.java

@@ -6,6 +6,9 @@
 package me.filoghost.holographicdisplays.core.base;
 
 import me.filoghost.holographicdisplays.api.Position;
+import me.filoghost.holographicdisplays.core.CoreGlobalConfig;
+import me.filoghost.holographicdisplays.core.CorePreconditions;
+import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
@@ -15,46 +18,54 @@ import java.util.List;
 
 public class BaseHologramLines<T extends EditableHologramLine> implements Iterable<T> {
 
-    public static double spaceBetweenLines;
-
     private final BaseHologram hologram;
+    private final LineTrackerManager lineTrackerManager;
     private final List<T> lines;
     private final List<T> unmodifiableLinesView;
 
-    public BaseHologramLines(BaseHologram hologram) {
+    public BaseHologramLines(BaseHologram hologram, LineTrackerManager lineTrackerManager) {
         this.hologram = hologram;
+        this.lineTrackerManager = lineTrackerManager;
         this.lines = new ArrayList<>();
         this.unmodifiableLinesView = Collections.unmodifiableList(lines);
     }
 
     @Override
     public Iterator<T> iterator() {
+        CorePreconditions.checkMainThread();
         return unmodifiableLinesView.iterator();
     }
 
     public int size() {
+        CorePreconditions.checkMainThread();
         return lines.size();
     }
 
     public @NotNull T get(int index) {
+        CorePreconditions.checkMainThread();
         return lines.get(index);
     }
 
     public void add(T line) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         lines.add(line);
+        lineTrackerManager.startTracking(line);
         updatePositions();
     }
 
     public void insert(int beforeIndex, T line) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         lines.add(beforeIndex, line);
+        lineTrackerManager.startTracking(line);
         updatePositions();
     }
 
     public void remove(int index) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         lines.remove(index).setDeleted();
@@ -62,6 +73,7 @@ public class BaseHologramLines<T extends EditableHologramLine> implements Iterab
     }
 
     public boolean remove(T line) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         boolean removed = lines.remove(line);
@@ -73,6 +85,7 @@ public class BaseHologramLines<T extends EditableHologramLine> implements Iterab
     }
 
     public void clear() {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         Iterator<T> iterator = lines.iterator();
@@ -98,7 +111,7 @@ public class BaseHologramLines<T extends EditableHologramLine> implements Iterab
 
             currentLineY -= line.getHeight();
             if (i > 0) {
-                currentLineY -= spaceBetweenLines;
+                currentLineY -= CoreGlobalConfig.spaceBetweenLines;
             }
 
             line.setCoordinates(hologramPosition.getX(), currentLineY, hologramPosition.getZ());
@@ -106,6 +119,8 @@ public class BaseHologramLines<T extends EditableHologramLine> implements Iterab
     }
 
     public double getHeight() {
+        CorePreconditions.checkMainThread();
+
         if (lines.isEmpty()) {
             return 0;
         }
@@ -116,7 +131,7 @@ public class BaseHologramLines<T extends EditableHologramLine> implements Iterab
             height += line.getHeight();
         }
 
-        height += spaceBetweenLines * (lines.size() - 1);
+        height += CoreGlobalConfig.spaceBetweenLines * (lines.size() - 1);
         return height;
     }
 

core/src/main/java/me/filoghost/holographicdisplays/core/base/BaseHologramManager.java

@@ -5,7 +5,7 @@
  */
 package me.filoghost.holographicdisplays.core.base;
 
-import me.filoghost.fcommons.Preconditions;
+import me.filoghost.holographicdisplays.core.CorePreconditions;
 import org.bukkit.Chunk;
 import org.bukkit.World;
 
@@ -21,7 +21,7 @@ public abstract class BaseHologramManager<H extends BaseHologram> {
     private final List<H> unmodifiableHologramsView = Collections.unmodifiableList(holograms);
 
     protected void addHologram(H hologram) {
-        Preconditions.checkMainThread("async hologram create");
+        CorePreconditions.checkMainThread();
 
         holograms.add(hologram);
     }
@@ -31,14 +31,14 @@ public abstract class BaseHologramManager<H extends BaseHologram> {
     }
 
     public void deleteHologram(H hologram) {
-        Preconditions.checkMainThread("async hologram delete");
+        CorePreconditions.checkMainThread();
 
         hologram.setDeleted();
         holograms.remove(hologram);
     }
 
     public void deleteHologramsIf(Predicate<H> condition) {
-        Preconditions.checkMainThread("async hologram delete");
+        CorePreconditions.checkMainThread();
 
         Iterator<H> iterator = holograms.iterator();
         while (iterator.hasNext()) {
@@ -51,7 +51,7 @@ public abstract class BaseHologramManager<H extends BaseHologram> {
     }
 
     public void deleteHolograms() {
-        Preconditions.checkMainThread("async hologram delete");
+        CorePreconditions.checkMainThread();
 
         Iterator<H> iterator = holograms.iterator();
         while (iterator.hasNext()) {

core/src/main/java/me/filoghost/holographicdisplays/core/base/BaseItemHologramLine.java

@@ -7,9 +7,8 @@ package me.filoghost.holographicdisplays.core.base;
 
 import me.filoghost.fcommons.Preconditions;
 import me.filoghost.fcommons.logging.Log;
+import me.filoghost.holographicdisplays.core.CorePreconditions;
 import me.filoghost.holographicdisplays.nms.common.entity.ItemNMSPacketEntity;
-import me.filoghost.holographicdisplays.core.tracking.ItemLineTracker;
-import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.jetbrains.annotations.Nullable;
@@ -23,31 +22,25 @@ public abstract class BaseItemHologramLine extends BaseClickableHologramLine {
         setItemStack(itemStack);
     }
 
-    @Override
-    public ItemLineTracker createTracker(LineTrackerManager trackerManager) {
-        return trackerManager.startTracking(this);
-    }
-
     public void onPickup(Player player) {
-        if (hasPickupCallback() && canInteract(player)) {
-            try {
-                invokePickupCallback(player);
-            } catch (Throwable t) {
-                Log.warning("The plugin " + getCreatorPlugin().getName() + " generated an exception"
-                        + " when the player " + player.getName() + " picked up an item from a hologram.", t);
-            }
+        try {
+            invokeExternalPickupCallback(player);
+        } catch (Throwable t) {
+            Log.warning("The plugin " + getCreatorPlugin().getName() + " generated an exception"
+                    + " when the player " + player.getName() + " picked up an item from a hologram.", t);
         }
     }
 
     public abstract boolean hasPickupCallback();
 
-    protected abstract void invokePickupCallback(Player player);
+    protected abstract void invokeExternalPickupCallback(Player player);
 
     public @Nullable ItemStack getItemStack() {
         return clone(itemStack);
     }
 
     public void setItemStack(@Nullable ItemStack itemStack) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         if (itemStack != null) {

core/src/main/java/me/filoghost/holographicdisplays/core/base/BaseTextHologramLine.java

@@ -5,9 +5,8 @@
  */
 package me.filoghost.holographicdisplays.core.base;
 
+import me.filoghost.holographicdisplays.core.CorePreconditions;
 import me.filoghost.holographicdisplays.nms.common.entity.TextNMSPacketEntity;
-import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
-import me.filoghost.holographicdisplays.core.tracking.TextLineTracker;
 import org.jetbrains.annotations.Nullable;
 
 public abstract class BaseTextHologramLine extends BaseClickableHologramLine {
@@ -21,16 +20,12 @@ public abstract class BaseTextHologramLine extends BaseClickableHologramLine {
 
     public abstract boolean isAllowPlaceholders();
 
-    @Override
-    protected TextLineTracker createTracker(LineTrackerManager trackerManager) {
-        return trackerManager.startTracking(this);
-    }
-
     public @Nullable String getText() {
         return text;
     }
 
     public void setText(@Nullable String text) {
+        CorePreconditions.checkMainThread();
         checkNotDeleted();
 
         this.text = text;

core/src/main/java/me/filoghost/holographicdisplays/core/listener/LineClickListener.java

@@ -5,9 +5,9 @@
  */
 package me.filoghost.holographicdisplays.core.listener;
 
+import me.filoghost.holographicdisplays.core.tracking.ClickableLineTracker;
 import me.filoghost.holographicdisplays.nms.common.EntityID;
 import me.filoghost.holographicdisplays.nms.common.PacketListener;
-import me.filoghost.holographicdisplays.core.base.BaseClickableHologramLine;
 import org.bukkit.entity.Player;
 
 import java.util.Collections;
@@ -17,22 +17,22 @@ import java.util.concurrent.ConcurrentMap;
 
 public class LineClickListener implements PacketListener {
 
-    private final ConcurrentMap<Integer, BaseClickableHologramLine> linesByEntityID;
+    private final ConcurrentMap<Integer, ClickableLineTracker<?>> lineTrackerByEntityID;
 
     // It is necessary to queue async click events to process them from the main thread.
     // Use a set to avoid duplicate click events to the same line.
     private final Set<QueuedClickEvent> queuedClickEvents;
 
     public LineClickListener() {
-        linesByEntityID = new ConcurrentHashMap<>();
+        lineTrackerByEntityID = new ConcurrentHashMap<>();
         queuedClickEvents = Collections.newSetFromMap(new ConcurrentHashMap<>());
     }
 
     @Override
     public boolean onAsyncEntityInteract(Player player, int entityID) {
-        BaseClickableHologramLine line = linesByEntityID.get(entityID);
-        if (line != null) {
-            queuedClickEvents.add(new QueuedClickEvent(player, line));
+        ClickableLineTracker<?> lineTracker = lineTrackerByEntityID.get(entityID);
+        if (lineTracker != null) {
+            queuedClickEvents.add(new QueuedClickEvent(player, lineTracker));
             return true;
         } else {
             return false;
@@ -41,19 +41,19 @@ public class LineClickListener implements PacketListener {
 
     // This method is called from the main thread
     public void processQueuedClickEvents() {
-        for (QueuedClickEvent queuedClickEvent : queuedClickEvents) {
-            queuedClickEvent.line.onClick(queuedClickEvent.player);
+        for (QueuedClickEvent event : queuedClickEvents) {
+            event.lineTracker.onClientClick(event.player);
         }
         queuedClickEvents.clear();
     }
 
-    public void registerLine(EntityID clickableEntityID, BaseClickableHologramLine line) {
-        linesByEntityID.put(clickableEntityID.getNumericID(), line);
+    public void addLineTracker(EntityID clickableEntityID, ClickableLineTracker<?> lineTracker) {
+        lineTrackerByEntityID.put(clickableEntityID.getNumericID(), lineTracker);
     }
 
-    public void unregisterLine(EntityID clickableEntityID) {
+    public void removeLineTracker(EntityID clickableEntityID) {
         if (clickableEntityID.hasInitializedNumericID()) {
-            linesByEntityID.remove(clickableEntityID.getNumericID());
+            lineTrackerByEntityID.remove(clickableEntityID.getNumericID());
         }
     }
 
@@ -61,11 +61,11 @@ public class LineClickListener implements PacketListener {
     private static class QueuedClickEvent {
 
         private final Player player;
-        private final BaseClickableHologramLine line;
+        private final ClickableLineTracker<?> lineTracker;
 
-        QueuedClickEvent(Player player, BaseClickableHologramLine line) {
+        QueuedClickEvent(Player player, ClickableLineTracker<?> lineTracker) {
             this.player = player;
-            this.line = line;
+            this.lineTracker = lineTracker;
         }
 
         @Override
@@ -78,13 +78,13 @@ public class LineClickListener implements PacketListener {
             }
 
             QueuedClickEvent other = (QueuedClickEvent) obj;
-            return this.player.equals(other.player) && this.line.equals(other.line);
+            return this.player.equals(other.player) && this.lineTracker.equals(other.lineTracker);
         }
 
         @Override
         public int hashCode() {
             int result = player.hashCode();
-            result = 31 * result + line.hashCode();
+            result = 31 * result + lineTracker.hashCode();
             return result;
         }
 

core/src/main/java/me/filoghost/holographicdisplays/core/placeholder/parsing/Parser.java

@@ -123,6 +123,22 @@ class Parser {
         }
     }
 
+    public static String addEscapes(String string) {
+        StringBuilder output = new StringBuilder(string.length() + 16); // String gets longer with escapes
+
+        for (int i = 0; i < string.length(); i++) {
+            char currentChar = string.charAt(i);
+
+            if (isSpecialCharacter(currentChar)) {
+                output.append(ESCAPE_CHAR);
+            }
+
+            output.append(currentChar);
+        }
+
+        return output.toString();
+    }
+
     private static boolean isSpecialCharacter(char currentChar) {
         return currentChar == ESCAPE_CHAR
                 || currentChar == PLACEHOLDER_START_CHAR

core/src/main/java/me/filoghost/holographicdisplays/core/placeholder/parsing/StringWithPlaceholders.java

@@ -27,6 +27,10 @@ public final class StringWithPlaceholders {
         return Parser.parse(string, true);
     }
 
+    public static String addEscapes(@NotNull String string) {
+        return Parser.addEscapes(string);
+    }
+
     StringWithPlaceholders(@NotNull String string, @Nullable List<Part> parts) {
         this.string = string;
         this.parts = parts;
@@ -71,7 +75,7 @@ public final class StringWithPlaceholders {
         return replace(player, replaceFunction, StringReplaceFunction.NO_REPLACEMENTS);
     }
 
-    public @NotNull String replaceStrings(StringReplaceFunction replaceFunction) {
+    public @NotNull String replaceOutsidePlaceholders(StringReplaceFunction replaceFunction) {
         return replace(null, PlaceholderReplaceFunction.NO_REPLACEMENTS, replaceFunction);
     }
 

core/src/main/java/me/filoghost/holographicdisplays/core/tick/TickingTask.java

@@ -6,6 +6,8 @@
 package me.filoghost.holographicdisplays.core.tick;
 
 import me.filoghost.fcommons.logging.Log;
+import me.filoghost.holographicdisplays.core.CoreGlobalConfig;
+import me.filoghost.holographicdisplays.core.NMSVersion;
 import me.filoghost.holographicdisplays.core.listener.LineClickListener;
 import me.filoghost.holographicdisplays.core.placeholder.tracking.ActivePlaceholderTracker;
 import me.filoghost.holographicdisplays.core.tracking.LineTrackerManager;
@@ -56,7 +58,24 @@ public class TickingTask implements Runnable {
     }
 
     public void onPlayerRespawn(Player player) {
-        lineTrackerManager.removeViewer(player);
+        switch (NMSVersion.getCurrent()) {
+            case v1_8_R1:
+            case v1_8_R2:
+            case v1_8_R3:
+            case v1_9_R1:
+            case v1_9_R2:
+            case v1_10_R1:
+            case v1_11_R1:
+            case v1_12_R1:
+            case v1_13_R1:
+            case v1_13_R2:
+            case v1_14_R1:
+                // For older versions, force spawn packets to be resent after the player respawns
+                lineTrackerManager.removeViewer(player);
+                break;
+            default:
+                break;
+        }
     }
 
     @Override
@@ -75,6 +94,9 @@ public class TickingTask implements Runnable {
 
         // Holograms need to disappear before chunks (code taken from Bukkit)
         int maxViewRange = (Bukkit.getViewDistance() - 1) * 16;
+        if (maxViewRange > CoreGlobalConfig.maxViewRange) {
+            maxViewRange = CoreGlobalConfig.maxViewRange;
+        }
 
         try {
             lineTrackerManager.update(onlinePlayers, movedPlayers, maxViewRange);

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/ClickableLineTracker.java

@@ -10,6 +10,8 @@ import me.filoghost.holographicdisplays.core.base.BaseClickableHologramLine;
 import me.filoghost.holographicdisplays.core.listener.LineClickListener;
 import me.filoghost.holographicdisplays.nms.common.NMSManager;
 import me.filoghost.holographicdisplays.nms.common.entity.ClickableNMSPacketEntity;
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
 import org.jetbrains.annotations.MustBeInvokedByOverriders;
 
 public abstract class ClickableLineTracker<T extends Viewer> extends LineTracker<T> {
@@ -27,14 +29,32 @@ public abstract class ClickableLineTracker<T extends Viewer> extends LineTracker
         this.lineClickListener = lineClickListener;
     }
 
+    public void onClientClick(Player player) {
+        if (getLine().hasClickCallback() && canInteract(player) && isInClickRange(player)) {
+            getLine().onClick(player);
+        }
+    }
+
+    private boolean isInClickRange(Player player) {
+        Location playerLocation = player.getLocation();
+        PositionCoordinates positionCoordinates = getLine().getCoordinates();
+
+        double xDiff = playerLocation.getX() - positionCoordinates.getX();
+        double yDiff = playerLocation.getY() + 1.3 - positionCoordinates.getY(); // Use shoulder height
+        double zDiff = playerLocation.getZ() - positionCoordinates.getZ();
+
+        double distanceSquared = (xDiff * xDiff) + (yDiff * yDiff) + (zDiff * zDiff);
+        return distanceSquared < 5 * 5;
+    }
+
     @Override
-    protected abstract BaseClickableHologramLine getLine();
+    public abstract BaseClickableHologramLine getLine();
 
     @MustBeInvokedByOverriders
     @Override
     public void onRemoval() {
         super.onRemoval();
-        lineClickListener.unregisterLine(clickableEntity.getID());
+        lineClickListener.removeLineTracker(clickableEntity.getID());
     }
 
     @MustBeInvokedByOverriders
@@ -47,9 +67,9 @@ public abstract class ClickableLineTracker<T extends Viewer> extends LineTracker
             this.spawnClickableEntity = spawnClickableEntity;
             this.spawnClickableEntityChanged = true;
             if (spawnClickableEntity) {
-                lineClickListener.registerLine(clickableEntity.getID(), getLine());
+                lineClickListener.addLineTracker(clickableEntity.getID(), this);
             } else {
-                lineClickListener.unregisterLine(clickableEntity.getID());
+                lineClickListener.removeLineTracker(clickableEntity.getID());
             }
         }
     }
@@ -65,7 +85,11 @@ public abstract class ClickableLineTracker<T extends Viewer> extends LineTracker
     @Override
     protected void sendSpawnPackets(Viewers<T> viewers) {
         if (spawnClickableEntity) {
-            viewers.sendPackets(clickableEntity.newSpawnPackets(getClickableEntityPosition()));
+            // Copy for async use
+            PositionCoordinates clickableEntityPosition = getClickableEntityPosition();
+            PacketSenderExecutor.execute(() -> {
+                viewers.sendPackets(clickableEntity.newSpawnPackets(clickableEntityPosition));
+            });
         }
     }
 
@@ -73,7 +97,9 @@ public abstract class ClickableLineTracker<T extends Viewer> extends LineTracker
     @Override
     protected void sendDestroyPackets(Viewers<T> viewers) {
         if (spawnClickableEntity) {
-            viewers.sendPackets(clickableEntity.newDestroyPackets());
+            PacketSenderExecutor.execute(() -> {
+                viewers.sendPackets(clickableEntity.newDestroyPackets());
+            });
         }
     }
 
@@ -84,9 +110,15 @@ public abstract class ClickableLineTracker<T extends Viewer> extends LineTracker
 
         if (spawnClickableEntityChanged) {
             if (spawnClickableEntity) {
-                viewers.sendPackets(clickableEntity.newSpawnPackets(getClickableEntityPosition()));
+                // Copy for async use
+                PositionCoordinates clickableEntityPosition = getClickableEntityPosition();
+                PacketSenderExecutor.execute(() -> {
+                    viewers.sendPackets(clickableEntity.newSpawnPackets(clickableEntityPosition));
+                });
             } else {
-                viewers.sendPackets(clickableEntity.newDestroyPackets());
+                PacketSenderExecutor.execute(() -> {
+                    viewers.sendPackets(clickableEntity.newDestroyPackets());
+                });
             }
         }
     }
@@ -95,7 +127,11 @@ public abstract class ClickableLineTracker<T extends Viewer> extends LineTracker
     @Override
     protected void sendPositionChangePackets(Viewers<T> viewers) {
         if (spawnClickableEntity) {
-            viewers.sendPackets(clickableEntity.newTeleportPackets(getClickableEntityPosition()));
+            // Copy for async use
+            PositionCoordinates clickableEntityPosition = getClickableEntityPosition();
+            PacketSenderExecutor.execute(() -> {
+                viewers.sendPackets(clickableEntity.newTeleportPackets(clickableEntityPosition));
+            });
         }
     }
 

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/ImmutableViewers.java

@@ -5,15 +5,16 @@
  */
 package me.filoghost.holographicdisplays.core.tracking;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.function.Consumer;
 
-public class DelegateViewers<T extends Viewer> implements Viewers<T> {
+public class ImmutableViewers<T extends Viewer> implements Viewers<T> {
 
     private final Collection<T> viewers;
 
-    public DelegateViewers(Collection<T> viewers) {
-        this.viewers = viewers;
+    public ImmutableViewers(Collection<T> viewers) {
+        this.viewers = new ArrayList<>(viewers);
     }
 
     @Override

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/ItemLineTracker.java

@@ -5,11 +5,14 @@
  */
 package me.filoghost.holographicdisplays.core.tracking;
 
+import me.filoghost.holographicdisplays.common.PositionCoordinates;
 import me.filoghost.holographicdisplays.core.base.BaseItemHologramLine;
 import me.filoghost.holographicdisplays.core.listener.LineClickListener;
 import me.filoghost.holographicdisplays.core.tick.CachedPlayer;
 import me.filoghost.holographicdisplays.nms.common.NMSManager;
 import me.filoghost.holographicdisplays.nms.common.entity.ItemNMSPacketEntity;
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.jetbrains.annotations.MustBeInvokedByOverriders;
 
@@ -48,13 +51,20 @@ public class ItemLineTracker extends ClickableLineTracker<Viewer> {
 
         if (spawnItemEntity && hasViewers() && line.hasPickupCallback()) {
             for (Viewer viewer : getViewers()) {
-                if (viewer.getLocation() != null && CollisionHelper.isInPickupRange(viewer.getLocation(), positionCoordinates)) {
-                    line.onPickup(viewer.getBukkitPlayer());
-                }
+                invokePickupIfNecessary(viewer);
             }
         }
     }
 
+    private void invokePickupIfNecessary(Viewer viewer) {
+        Location location = viewer.getLocation();
+        Player player = viewer.getBukkitPlayer();
+
+        if (location != null && CollisionHelper.isInPickupRange(location, positionCoordinates) && canInteract(player)) {
+            line.onPickup(player);
+        }
+    }
+
     @Override
     protected boolean updatePlaceholders() {
         return false;
@@ -97,7 +107,12 @@ public class ItemLineTracker extends ClickableLineTracker<Viewer> {
         super.sendSpawnPackets(viewers);
 
         if (spawnItemEntity) {
-            viewers.sendPackets(itemEntity.newSpawnPackets(positionCoordinates, itemStack));
+            // Copy for async use
+            PositionCoordinates positionCoordinates = this.positionCoordinates;
+            ItemStack itemStack = this.itemStack;
+            PacketSenderExecutor.execute(() -> {
+                viewers.sendPackets(itemEntity.newSpawnPackets(positionCoordinates, itemStack));
+            });
         }
     }
 
@@ -107,7 +122,9 @@ public class ItemLineTracker extends ClickableLineTracker<Viewer> {
         super.sendDestroyPackets(viewers);
 
         if (spawnItemEntity) {
-            viewers.sendPackets(itemEntity.newDestroyPackets());
+            PacketSenderExecutor.execute(() -> {
+                viewers.sendPackets(itemEntity.newDestroyPackets());
+            });
         }
     }
 
@@ -118,13 +135,24 @@ public class ItemLineTracker extends ClickableLineTracker<Viewer> {
 
         if (spawnItemEntityChanged) {
             if (spawnItemEntity) {
-                viewers.sendPackets(itemEntity.newSpawnPackets(positionCoordinates, itemStack));
+                // Copy for async use
+                PositionCoordinates positionCoordinates = this.positionCoordinates;
+                ItemStack itemStack = this.itemStack;
+                PacketSenderExecutor.execute(() -> {
+                    viewers.sendPackets(itemEntity.newSpawnPackets(positionCoordinates, itemStack));
+                });
             } else {
-                viewers.sendPackets(itemEntity.newDestroyPackets());
+                PacketSenderExecutor.execute(() -> {
+                    viewers.sendPackets(itemEntity.newDestroyPackets());
+                });
             }
         } else if (itemStackChanged) {
             // Only send item changes if full spawn/destroy packets were not sent
-            viewers.sendPackets(itemEntity.newChangePackets(itemStack));
+            // Copy for async use
+            ItemStack itemStack = this.itemStack;
+            PacketSenderExecutor.execute(() -> {
+                viewers.sendPackets(itemEntity.newChangePackets(itemStack));
+            });
         }
     }
 
@@ -134,7 +162,11 @@ public class ItemLineTracker extends ClickableLineTracker<Viewer> {
         super.sendPositionChangePackets(viewers);
 
         if (spawnItemEntity) {
-            viewers.sendPackets(itemEntity.newTeleportPackets(positionCoordinates));
+            // Copy for async use
+            PositionCoordinates positionCoordinates = this.positionCoordinates;
+            PacketSenderExecutor.execute(() -> {
+                viewers.sendPackets(itemEntity.newTeleportPackets(positionCoordinates));
+            });
         }
     }
 

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/LineTracker.java

@@ -8,35 +8,30 @@ package me.filoghost.holographicdisplays.core.tracking;
 import me.filoghost.holographicdisplays.common.PositionCoordinates;
 import me.filoghost.holographicdisplays.core.base.BaseHologramLine;
 import me.filoghost.holographicdisplays.core.tick.CachedPlayer;
+import org.bukkit.GameMode;
 import org.bukkit.Location;
 import org.bukkit.entity.Player;
 import org.jetbrains.annotations.MustBeInvokedByOverriders;
 
 import java.util.Collection;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 public abstract class LineTracker<T extends Viewer> {
 
-    private final Map<Player, T> viewers;
-    private final Viewers<T> iterableViewers;
+    private final ConcurrentMap<Player, T> viewers;
 
     private String positionWorldName;
     protected PositionCoordinates positionCoordinates;
     private boolean positionChanged;
 
-    /**
-     * Flag to indicate that the line has changed in some way and there could be the need to send update packets.
-     */
-    private boolean lineChanged;
     private boolean inLoadedChunk;
     private int lastVisibilitySettingsVersion;
 
     protected LineTracker() {
-        this.viewers = new HashMap<>();
-        this.iterableViewers = new DelegateViewers<>(viewers.values());
+        this.viewers = new ConcurrentHashMap<>();
     }
 
     protected abstract BaseHologramLine getLine();
@@ -50,17 +45,13 @@ public abstract class LineTracker<T extends Viewer> {
         resetViewersAndSendDestroyPackets();
     }
 
-    public final void setLineChanged() {
-        lineChanged = true;
-    }
-
     @MustBeInvokedByOverriders
     protected void update(List<CachedPlayer> onlinePlayers, List<CachedPlayer> movedPlayers, int maxViewRange) {
         boolean sendChangesPackets = false;
 
         // First, detect the changes if the flag is on and set it off
-        if (lineChanged) {
-            lineChanged = false;
+        if (getLine().hasChanged()) {
+            getLine().clearChanged();
             detectChanges();
             sendChangesPackets = true;
         }
@@ -74,7 +65,7 @@ public abstract class LineTracker<T extends Viewer> {
 
         // Then, send the changes (if any) to already tracked players
         if (sendChangesPackets && hasViewers()) {
-            sendChangesPackets(iterableViewers);
+            sendChangesPackets(new ImmutableViewers<>(viewers.values()));
         }
 
         // Finally, add/remove viewers sending them the full spawn/destroy packets
@@ -189,7 +180,7 @@ public abstract class LineTracker<T extends Viewer> {
         return viewers.values();
     }
 
-    public final boolean isViewer(Player player) {
+    protected final boolean isViewer(Player player) {
         return viewers.containsKey(player);
     }
 
@@ -197,6 +188,14 @@ public abstract class LineTracker<T extends Viewer> {
         viewers.remove(player);
     }
 
+    protected boolean canInteract(Player player) {
+        return !getLine().isDeleted()
+                && player.isOnline()
+                && player.getGameMode() != GameMode.SPECTATOR
+                && isViewer(player)
+                && getLine().isVisibleTo(player);
+    }
+
     @MustBeInvokedByOverriders
     protected void detectChanges() {
         PositionCoordinates positionCoordinates = getLine().getCoordinates();
@@ -222,7 +221,7 @@ public abstract class LineTracker<T extends Viewer> {
             return;
         }
 
-        sendDestroyPackets(iterableViewers);
+        sendDestroyPackets(new ImmutableViewers<>(viewers.values()));
         viewers.clear();
     }
 

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/LineTrackerManager.java

@@ -7,6 +7,7 @@ package me.filoghost.holographicdisplays.core.tracking;
 
 import me.filoghost.holographicdisplays.core.base.BaseItemHologramLine;
 import me.filoghost.holographicdisplays.core.base.BaseTextHologramLine;
+import me.filoghost.holographicdisplays.core.base.EditableHologramLine;
 import me.filoghost.holographicdisplays.core.listener.LineClickListener;
 import me.filoghost.holographicdisplays.core.placeholder.tracking.ActivePlaceholderTracker;
 import me.filoghost.holographicdisplays.core.tick.CachedPlayer;
@@ -35,16 +36,14 @@ public class LineTrackerManager {
         this.lineTrackers = new LinkedList<>();
     }
 
-    public TextLineTracker startTracking(BaseTextHologramLine line) {
-        TextLineTracker tracker = new TextLineTracker(line, nmsManager, lineClickListener, placeholderTracker);
-        lineTrackers.add(tracker);
-        return tracker;
-    }
-
-    public ItemLineTracker startTracking(BaseItemHologramLine line) {
-        ItemLineTracker tracker = new ItemLineTracker(line, nmsManager, lineClickListener);
-        lineTrackers.add(tracker);
-        return tracker;
+    public <T extends EditableHologramLine> void startTracking(T line) {
+        if (line instanceof BaseTextHologramLine) {
+            lineTrackers.add(new TextLineTracker((BaseTextHologramLine) line, nmsManager, lineClickListener, placeholderTracker));
+        } else if (line instanceof BaseItemHologramLine) {
+            lineTrackers.add(new ItemLineTracker((BaseItemHologramLine) line, nmsManager, lineClickListener));
+        } else {
+            throw new UnsupportedOperationException("unsupported line class: " + line.getClass().getName());
+        }
     }
 
     public void update(List<CachedPlayer> onlinePlayers, List<CachedPlayer> movedPlayers, int maxViewRange) {

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/MutableViewers.java

@@ -15,7 +15,7 @@ public class MutableViewers<T extends Viewer> implements Viewers<T> {
     private T viewer;
     private List<T> additionalViewers;
 
-    public void add(T viewer) {
+    public synchronized void add(T viewer) {
         if (this.viewer == null) {
             this.viewer = viewer;
         } else {
@@ -27,7 +27,7 @@ public class MutableViewers<T extends Viewer> implements Viewers<T> {
     }
 
     @Override
-    public void forEach(Consumer<? super T> action) {
+    public synchronized void forEach(Consumer<? super T> action) {
         if (viewer != null) {
             action.accept(viewer);
             if (additionalViewers != null) {

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/PacketSenderExecutor.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) filoghost and contributors
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+package me.filoghost.holographicdisplays.core.tracking;
+
+import me.filoghost.fcommons.logging.Log;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+/**
+ * This is a quick but ugly helper class for creating and sending packets async.
+ * Static classes like this should be avoided.
+ * Important note: this executor can only have one thread, as packets must be sent in a precise order.
+ */
+public class PacketSenderExecutor {
+
+    private static volatile BlockingQueue<Runnable> tasks;
+
+    private static final Runnable STOP_MARKER_TASK = () -> {};
+
+    public static void execute(Runnable task) {
+        tasks.add(task);
+    }
+
+    public static void start() {
+        tasks = new LinkedBlockingQueue<>();
+        Thread thread = new Thread(() -> {
+            while (true) {
+                try {
+                    Runnable task = tasks.take();
+                    if (task == STOP_MARKER_TASK) {
+                        return;
+                    }
+                    task.run();
+                } catch (Throwable t) {
+                    Log.severe("Error in packet sender task", t);
+                }
+            }
+        });
+        thread.setName("Holographic Displays async packets");
+        thread.start();
+    }
+
+    public static void stopGracefully() {
+        if (tasks != null) {
+            tasks.add(STOP_MARKER_TASK);
+        }
+    }
+
+}

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/TextLineTracker.java

@@ -5,6 +5,7 @@
  */
 package me.filoghost.holographicdisplays.core.tracking;
 
+import me.filoghost.holographicdisplays.common.PositionCoordinates;
 import me.filoghost.holographicdisplays.core.base.BaseTextHologramLine;
 import me.filoghost.holographicdisplays.core.listener.LineClickListener;
 import me.filoghost.holographicdisplays.core.placeholder.tracking.ActivePlaceholderTracker;
@@ -84,15 +85,22 @@ public class TextLineTracker extends ClickableLineTracker<TextLineViewer> {
     protected void sendSpawnPackets(Viewers<TextLineViewer> viewers) {
         super.sendSpawnPackets(viewers);
 
-        IndividualTextPacketGroup spawnPackets = textEntity.newSpawnPackets(positionCoordinates);
-        viewers.forEach(viewer -> viewer.sendTextPackets(spawnPackets));
+        // Copy for async use
+        PositionCoordinates positionCoordinates = this.positionCoordinates;
+        viewers.forEach(TextLineViewer::updateNextTextToSend);
+        PacketSenderExecutor.execute(() -> {
+            IndividualTextPacketGroup spawnPackets = textEntity.newSpawnPackets(positionCoordinates);
+            viewers.forEach(viewer -> viewer.sendTextPackets(spawnPackets));
+        });
     }
 
     @MustBeInvokedByOverriders
     @Override
     protected void sendDestroyPackets(Viewers<TextLineViewer> viewers) {
         super.sendDestroyPackets(viewers);
-        viewers.sendPackets(textEntity.newDestroyPackets());
+        PacketSenderExecutor.execute(() -> {
+            viewers.sendPackets(textEntity.newDestroyPackets());
+        });
     }
 
     @Override
@@ -100,8 +108,11 @@ public class TextLineTracker extends ClickableLineTracker<TextLineViewer> {
         super.sendChangesPackets(viewers);
 
         if (displayTextChanged) {
-            IndividualTextPacketGroup changePackets = textEntity.newChangePackets();
-            viewers.forEach(viewer -> viewer.sendTextPacketsIfNecessary(changePackets));
+            viewers.forEach(TextLineViewer::updateNextTextToSend);
+            PacketSenderExecutor.execute(() -> {
+                IndividualTextPacketGroup changePackets = textEntity.newChangePackets();
+                viewers.forEach(viewer -> viewer.sendTextPacketsIfNecessary(changePackets));
+            });
         }
     }
 
@@ -109,7 +120,11 @@ public class TextLineTracker extends ClickableLineTracker<TextLineViewer> {
     @Override
     protected void sendPositionChangePackets(Viewers<TextLineViewer> viewers) {
         super.sendPositionChangePackets(viewers);
-        viewers.sendPackets(textEntity.newTeleportPackets(positionCoordinates));
+        // Copy for async use
+        PositionCoordinates positionCoordinates = this.positionCoordinates;
+        PacketSenderExecutor.execute(() -> {
+            viewers.sendPackets(textEntity.newTeleportPackets(positionCoordinates));
+        });
     }
 
     @Override

core/src/main/java/me/filoghost/holographicdisplays/core/tracking/TextLineViewer.java

@@ -5,9 +5,8 @@
  */
 package me.filoghost.holographicdisplays.core.tracking;
 
-import me.filoghost.holographicdisplays.nms.common.IndividualTextPacketGroup;
 import me.filoghost.holographicdisplays.core.tick.CachedPlayer;
-import org.jetbrains.annotations.Nullable;
+import me.filoghost.holographicdisplays.nms.common.IndividualTextPacketGroup;
 
 import java.util.Objects;
 
@@ -15,8 +14,10 @@ class TextLineViewer extends Viewer {
 
     private final DisplayText displayText;
 
+    // Access to these variables must be synchronized, they are accessed from multiple threads
     private String individualText;
     private String lastSentText;
+    private String nextTextToSend;
 
     TextLineViewer(CachedPlayer player, DisplayText displayText) {
         super(player);
@@ -24,39 +25,47 @@ class TextLineViewer extends Viewer {
     }
 
     public void sendTextPackets(IndividualTextPacketGroup packets) {
-        String text = getOrComputeText();
-        this.lastSentText = text;
+        String text;
+        synchronized (this) {
+            text = nextTextToSend;
+            this.lastSentText = text;
+        }
         sendIndividualPackets(packets, text);
     }
 
     public void sendTextPacketsIfNecessary(IndividualTextPacketGroup packets) {
-        String text = getOrComputeText();
-        if (Objects.equals(lastSentText, text)) {
-            return; // Avoid sending unnecessary packets
+        String text;
+        synchronized (this) {
+            text = nextTextToSend;
+            if (Objects.equals(lastSentText, text)) {
+                return; // Avoid sending unnecessary packets
+            }
+            this.lastSentText = text;
         }
-        this.lastSentText = text;
         sendIndividualPackets(packets, text);
     }
 
-    private @Nullable String getOrComputeText() {
+    public synchronized void updateNextTextToSend() {
         if (displayText.containsIndividualPlaceholders()) {
             if (individualText == null) {
                 individualText = displayText.computeIndividualText(this);
             }
-            return individualText;
+            nextTextToSend = individualText;
         } else {
             individualText = null;
-            return displayText.getGlobalText();
+            nextTextToSend = displayText.getGlobalText();
         }
     }
 
     public boolean updateIndividualText() {
         String individualText = displayText.computeIndividualText(this);
-        if (!Objects.equals(this.individualText, individualText)) {
-            this.individualText = individualText;
-            return true;
-        } else {
-            return false;
+        synchronized (this) {
+            if (!Objects.equals(this.individualText, individualText)) {
+                this.individualText = individualText;
+                return true;
+            } else {
+                return false;
+            }
         }
     }
 

core/src/test/java/me/filoghost/holographicdisplays/core/placeholder/parsing/StringWithPlaceholdersTest.java

@@ -37,6 +37,8 @@ class StringWithPlaceholdersTest {
                 Arguments.of(" {p} ", " # "),
                 Arguments.of("{p} {p} {p}", "# # #"),
                 Arguments.of("{{p}}", "{#}"), // Only the innermost placeholder should be replaced
+                Arguments.of("{{p}", "{#"),
+                Arguments.of("{p}}", "#}"),
                 Arguments.of("{p abc", "{p abc"), // Placeholder without closing tag
                 Arguments.of("abc p}", "abc p}") // Placeholder without opening tag
         );
@@ -46,7 +48,7 @@ class StringWithPlaceholdersTest {
     @MethodSource("replaceLiteralPartsTestArguments")
     void replaceLiteralParts(String input, String expectedOutput) {
         StringWithPlaceholders s = StringWithPlaceholders.of(input);
-        assertThat(s.replaceStrings(literalPart -> "_")).isEqualTo(expectedOutput);
+        assertThat(s.replaceOutsidePlaceholders(literalPart -> "_")).isEqualTo(expectedOutput);
     }
 
     static Stream<Arguments> replaceLiteralPartsTestArguments() {
@@ -112,7 +114,7 @@ class StringWithPlaceholdersTest {
     @ParameterizedTest(name = "[{index}] {0} -> {0}")
     @MethodSource("escapesTestArguments")
     void preservingEscapes(String input) {
-        String output = StringWithPlaceholders.withEscapes(input).replaceStrings(StringReplaceFunction.NO_REPLACEMENTS);
+        String output = StringWithPlaceholders.withEscapes(input).replaceOutsidePlaceholders(StringReplaceFunction.NO_REPLACEMENTS);
         assertThat(output).isEqualTo(input);
     }
 
@@ -133,4 +135,10 @@ class StringWithPlaceholdersTest {
         );
     }
 
+    @Test
+    void addEscapes() {
+        String escaped = StringWithPlaceholders.addEscapes("} { \\");
+        assertThat(escaped).isEqualTo("\\} \\{ \\\\");
+    }
+
 }

example/death-holograms/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-example</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-example-deathholograms</artifactId>

example/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-parent</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-example</artifactId>

example/power-ups/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-example</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-example-powerups</artifactId>

legacy-api/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-parent</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-legacy-api</artifactId>

legacy-api/v1/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-legacy-api</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-legacy-api-v1</artifactId>

legacy-api/v2/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-legacy-api</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-legacy-api-v2</artifactId>

nms/common/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-nms</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-nms-common</artifactId>

nms/pom.xml

@@ -1,42 +1,45 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-
-    <parent>
-        <groupId>me.filoghost.holographicdisplays</groupId>
-        <artifactId>holographicdisplays-parent</artifactId>
-        <version>3.0.0</version>
-    </parent>
-
-    <artifactId>holographicdisplays-nms</artifactId>
-    <name>HolographicDisplays NMS</name>
-    <packaging>pom</packaging>
-
-    <modules>
-        <module>common</module>
-        <module>v1_8_r3</module>
-        <module>v1_9_r2</module>
-        <module>v1_10_r1</module>
-        <module>v1_11_r1</module>
-        <module>v1_12_r1</module>
-        <module>v1_13_r2</module>
-        <module>v1_14_r1</module>
-        <module>v1_15_r1</module>
-        <module>v1_16_r1</module>
-        <module>v1_16_r2</module>
-        <module>v1_16_r3</module>
-        <module>v1_17_r1</module>
-        <module>v1_18_r1</module>
-        <module>v1_18_r2</module>
-        <module>v1_19_r1</module>
-    </modules>
-
-    <dependencies>
-        <dependency>
-            <groupId>me.filoghost.fcommons</groupId>
-            <artifactId>fcommons</artifactId>
-        </dependency>
-    </dependencies>
-
-</project>
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>me.filoghost.holographicdisplays</groupId>
+        <artifactId>holographicdisplays-parent</artifactId>
+        <version>3.0.5-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>holographicdisplays-nms</artifactId>
+    <name>HolographicDisplays NMS</name>
+    <packaging>pom</packaging>
+
+    <modules>
+        <module>common</module>
+        <module>v1_8_r3</module>
+        <module>v1_9_r2</module>
+        <module>v1_10_r1</module>
+        <module>v1_11_r1</module>
+        <module>v1_12_r1</module>
+        <module>v1_13_r2</module>
+        <module>v1_14_r1</module>
+        <module>v1_15_r1</module>
+        <module>v1_16_r3</module>
+        <module>v1_17_r1</module>
+        <module>v1_18_r1</module>
+        <module>v1_18_r2</module>
+        <module>v1_19_r1</module>
+        <module>v1_19_r2</module>
+        <module>v1_19_r3</module>
+        <module>v1_20_r1</module>
+        <module>v1_20_r2</module>
+        <module>v1_20_r3</module>
+    </modules>
+
+    <dependencies>
+        <dependency>
+            <groupId>me.filoghost.fcommons</groupId>
+            <artifactId>fcommons</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

nms/v1_10_r1/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-nms</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-nms-v1_10_r1</artifactId>

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/EntityLivingSpawnNMSPacket.java

@@ -62,7 +62,7 @@ class EntityLivingSpawnNMSPacket extends VersionNMSPacket {
         // Entries are deserialized and saved into a field which is not used during the re-serialization, set as empty
         packetByteBuffer.writeDataWatcherEntriesEnd();
 
-        Packet<?> rawPacket = writeData(new PacketPlayOutSpawnEntityLiving(), packetByteBuffer);
+        Packet<?> rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntityLiving());
         return new Builder(rawPacket, PacketByteBuffer.get());
     }
 

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/EntityMetadataNMSPacket.java

@@ -14,7 +14,7 @@ class EntityMetadataNMSPacket extends VersionNMSPacket {
     private final Packet<?> rawPacket;
 
     private EntityMetadataNMSPacket(PacketByteBuffer packetByteBuffer) {
-        this.rawPacket = writeData(new PacketPlayOutEntityMetadata(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityMetadata());
     }
 
     @Override

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/EntityMountNMSPacket.java

@@ -19,7 +19,7 @@ class EntityMountNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeVarInt(vehicleEntityID.getNumericID());
         packetByteBuffer.writeVarIntArray(passengerEntityID.getNumericID());
 
-        this.rawPacket = writeData(new PacketPlayOutMount(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutMount());
     }
 
     @Override

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/EntitySpawnNMSPacket.java

@@ -42,7 +42,7 @@ class EntitySpawnNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeShort(0);
         packetByteBuffer.writeShort(0);
 
-        this.rawPacket = writeData(new PacketPlayOutSpawnEntity(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntity());
     }
 
     @Override

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/EntityTeleportNMSPacket.java

@@ -31,7 +31,7 @@ class EntityTeleportNMSPacket extends VersionNMSPacket {
         // On ground
         packetByteBuffer.writeBoolean(false);
 
-        this.rawPacket = writeData(new PacketPlayOutEntityTeleport(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityTeleport());
     }
 
     @Override

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/PacketByteBuffer.java

@@ -6,25 +6,58 @@
 package me.filoghost.holographicdisplays.nms.v1_10_R1;
 
 import io.netty.buffer.Unpooled;
+import net.minecraft.server.v1_10_R1.Packet;
 import net.minecraft.server.v1_10_R1.PacketDataSerializer;
 
+import java.io.IOException;
 import java.util.UUID;
 
-class PacketByteBuffer extends PacketDataSerializer {
+class PacketByteBuffer {
 
-    private static final PacketByteBuffer INSTANCE = new PacketByteBuffer();
+    private static final ThreadLocal<PacketByteBuffer> LOCAL_INSTANCE = ThreadLocal.withInitial(PacketByteBuffer::new);
+
+    private final PacketDataSerializer serializer;
 
     static PacketByteBuffer get() {
-        INSTANCE.clear();
-        return INSTANCE;
+        PacketByteBuffer instance = LOCAL_INSTANCE.get();
+        instance.clear();
+        return instance;
     }
 
     private PacketByteBuffer() {
-        super(Unpooled.buffer());
+        this.serializer = new PacketDataSerializer(Unpooled.buffer());
+    }
+
+    int readableBytes() {
+        return serializer.readableBytes();
+    }
+
+    void readBytes(byte[] bytes) {
+        serializer.readBytes(bytes);
+    }
+
+    void writeBoolean(boolean flag) {
+        serializer.writeBoolean(flag);
+    }
+
+    void writeByte(int i) {
+        serializer.writeByte(i);
+    }
+
+    void writeShort(int i) {
+        serializer.writeShort(i);
+    }
+
+    void writeInt(int i) {
+        serializer.writeInt(i);
+    }
+
+    void writeDouble(double d) {
+        serializer.writeDouble(d);
     }
 
     void writeVarInt(int i) {
-        super.d(i);
+        serializer.d(i);
     }
 
     void writeVarIntArray(int i1) {
@@ -33,17 +66,31 @@ class PacketByteBuffer extends PacketDataSerializer {
     }
 
     void writeUUID(UUID uuid) {
-        super.a(uuid);
+        serializer.a(uuid);
     }
 
     <T> void writeDataWatcherEntry(DataWatcherKey<T> key, T value) {
-        writeByte(key.getIndex());
+        serializer.writeByte(key.getIndex());
         writeVarInt(key.getSerializerTypeID());
-        key.getSerializer().a(this, value);
+        key.getSerializer().a(serializer, value);
     }
 
     void writeDataWatcherEntriesEnd() {
-        writeByte(0xFF);
+        serializer.writeByte(0xFF);
+    }
+
+    void clear() {
+        serializer.clear();
+    }
+
+    <T extends Packet<?>> T writeDataTo(T packet) {
+        try {
+            packet.a(serializer);
+            return packet;
+        } catch (IOException e) {
+            // Never thrown by the implementations
+            throw new RuntimeException(e);
+        }
     }
 
 }

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/VersionNMSManager.java

@@ -8,6 +8,7 @@ package me.filoghost.holographicdisplays.nms.v1_10_R1;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelPipeline;
+import io.netty.channel.EventLoop;
 import me.filoghost.fcommons.logging.ErrorCollector;
 import me.filoghost.fcommons.logging.Log;
 import me.filoghost.fcommons.reflection.ReflectField;
@@ -115,8 +116,12 @@ public class VersionNMSManager implements NMSManager {
         PlayerConnection playerConnection = ((CraftPlayer) player).getHandle().playerConnection;
         NetworkManager networkManager = playerConnection.a();
         Channel channel = networkManager.channel;
+        if (channel == null) {
+            return;
+        }
+        EventLoop eventLoop = channel.eventLoop();
 
-        channel.eventLoop().execute(() -> {
+        Runnable safeModifierTask = () -> {
             if (!player.isOnline()) {
                 return;
             }
@@ -125,7 +130,13 @@ public class VersionNMSManager implements NMSManager {
             } catch (Exception e) {
                 Log.warning(NMSErrors.EXCEPTION_MODIFYING_CHANNEL_PIPELINE, e);
             }
-        });
+        };
+
+        if (eventLoop.inEventLoop()) {
+            safeModifierTask.run();
+        } else {
+            eventLoop.execute(safeModifierTask);
+        }
     }
 
 }

nms/v1_10_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_10_R1/VersionNMSPacket.java

@@ -10,8 +10,6 @@ import net.minecraft.server.v1_10_R1.Packet;
 import org.bukkit.craftbukkit.v1_10_R1.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 
-import java.io.IOException;
-
 abstract class VersionNMSPacket implements PacketGroup {
 
     @Override
@@ -21,14 +19,4 @@ abstract class VersionNMSPacket implements PacketGroup {
 
     abstract Packet<?> getRawPacket();
 
-    protected static <T extends Packet<?>> T writeData(T packet, PacketByteBuffer packetByteBuffer) {
-        try {
-            packet.a(packetByteBuffer);
-            return packet;
-        } catch (IOException e) {
-            // Never thrown by the implementations
-            throw new RuntimeException(e);
-        }
-    }
-
 }

nms/v1_11_r1/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-nms</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-nms-v1_11_r1</artifactId>

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/EntityLivingSpawnNMSPacket.java

@@ -62,7 +62,7 @@ class EntityLivingSpawnNMSPacket extends VersionNMSPacket {
         // Entries are deserialized and saved into a field which is not used during the re-serialization, set as empty
         packetByteBuffer.writeDataWatcherEntriesEnd();
 
-        Packet<?> rawPacket = writeData(new PacketPlayOutSpawnEntityLiving(), packetByteBuffer);
+        Packet<?> rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntityLiving());
         return new Builder(rawPacket, PacketByteBuffer.get());
     }
 

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/EntityMetadataNMSPacket.java

@@ -14,7 +14,7 @@ class EntityMetadataNMSPacket extends VersionNMSPacket {
     private final Packet<?> rawPacket;
 
     private EntityMetadataNMSPacket(PacketByteBuffer packetByteBuffer) {
-        this.rawPacket = writeData(new PacketPlayOutEntityMetadata(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityMetadata());
     }
 
     @Override

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/EntityMountNMSPacket.java

@@ -19,7 +19,7 @@ class EntityMountNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeVarInt(vehicleEntityID.getNumericID());
         packetByteBuffer.writeVarIntArray(passengerEntityID.getNumericID());
 
-        this.rawPacket = writeData(new PacketPlayOutMount(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutMount());
     }
 
     @Override

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/EntitySpawnNMSPacket.java

@@ -42,7 +42,7 @@ class EntitySpawnNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeShort(0);
         packetByteBuffer.writeShort(0);
 
-        this.rawPacket = writeData(new PacketPlayOutSpawnEntity(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntity());
     }
 
     @Override

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/EntityTeleportNMSPacket.java

@@ -31,7 +31,7 @@ class EntityTeleportNMSPacket extends VersionNMSPacket {
         // On ground
         packetByteBuffer.writeBoolean(false);
 
-        this.rawPacket = writeData(new PacketPlayOutEntityTeleport(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityTeleport());
     }
 
     @Override

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/PacketByteBuffer.java

@@ -6,25 +6,58 @@
 package me.filoghost.holographicdisplays.nms.v1_11_R1;
 
 import io.netty.buffer.Unpooled;
+import net.minecraft.server.v1_11_R1.Packet;
 import net.minecraft.server.v1_11_R1.PacketDataSerializer;
 
+import java.io.IOException;
 import java.util.UUID;
 
-class PacketByteBuffer extends PacketDataSerializer {
+class PacketByteBuffer {
 
-    private static final PacketByteBuffer INSTANCE = new PacketByteBuffer();
+    private static final ThreadLocal<PacketByteBuffer> LOCAL_INSTANCE = ThreadLocal.withInitial(PacketByteBuffer::new);
+
+    private final PacketDataSerializer serializer;
 
     static PacketByteBuffer get() {
-        INSTANCE.clear();
-        return INSTANCE;
+        PacketByteBuffer instance = LOCAL_INSTANCE.get();
+        instance.clear();
+        return instance;
     }
 
     private PacketByteBuffer() {
-        super(Unpooled.buffer());
+        this.serializer = new PacketDataSerializer(Unpooled.buffer());
+    }
+
+    int readableBytes() {
+        return serializer.readableBytes();
+    }
+
+    void readBytes(byte[] bytes) {
+        serializer.readBytes(bytes);
+    }
+
+    void writeBoolean(boolean flag) {
+        serializer.writeBoolean(flag);
+    }
+
+    void writeByte(int i) {
+        serializer.writeByte(i);
+    }
+
+    void writeShort(int i) {
+        serializer.writeShort(i);
+    }
+
+    void writeInt(int i) {
+        serializer.writeInt(i);
+    }
+
+    void writeDouble(double d) {
+        serializer.writeDouble(d);
     }
 
     void writeVarInt(int i) {
-        super.d(i);
+        serializer.d(i);
     }
 
     void writeVarIntArray(int i1) {
@@ -33,17 +66,31 @@ class PacketByteBuffer extends PacketDataSerializer {
     }
 
     void writeUUID(UUID uuid) {
-        super.a(uuid);
+        serializer.a(uuid);
     }
 
     <T> void writeDataWatcherEntry(DataWatcherKey<T> key, T value) {
-        writeByte(key.getIndex());
+        serializer.writeByte(key.getIndex());
         writeVarInt(key.getSerializerTypeID());
-        key.getSerializer().a(this, value);
+        key.getSerializer().a(serializer, value);
     }
 
     void writeDataWatcherEntriesEnd() {
-        writeByte(0xFF);
+        serializer.writeByte(0xFF);
+    }
+
+    void clear() {
+        serializer.clear();
+    }
+
+    <T extends Packet<?>> T writeDataTo(T packet) {
+        try {
+            packet.a(serializer);
+            return packet;
+        } catch (IOException e) {
+            // Never thrown by the implementations
+            throw new RuntimeException(e);
+        }
     }
 
 }

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/VersionNMSManager.java

@@ -8,6 +8,7 @@ package me.filoghost.holographicdisplays.nms.v1_11_R1;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelPipeline;
+import io.netty.channel.EventLoop;
 import me.filoghost.fcommons.logging.ErrorCollector;
 import me.filoghost.fcommons.logging.Log;
 import me.filoghost.fcommons.reflection.ReflectField;
@@ -115,8 +116,12 @@ public class VersionNMSManager implements NMSManager {
         PlayerConnection playerConnection = ((CraftPlayer) player).getHandle().playerConnection;
         NetworkManager networkManager = playerConnection.a();
         Channel channel = networkManager.channel;
+        if (channel == null) {
+            return;
+        }
+        EventLoop eventLoop = channel.eventLoop();
 
-        channel.eventLoop().execute(() -> {
+        Runnable safeModifierTask = () -> {
             if (!player.isOnline()) {
                 return;
             }
@@ -125,7 +130,13 @@ public class VersionNMSManager implements NMSManager {
             } catch (Exception e) {
                 Log.warning(NMSErrors.EXCEPTION_MODIFYING_CHANNEL_PIPELINE, e);
             }
-        });
+        };
+
+        if (eventLoop.inEventLoop()) {
+            safeModifierTask.run();
+        } else {
+            eventLoop.execute(safeModifierTask);
+        }
     }
 
 }

nms/v1_11_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_11_R1/VersionNMSPacket.java

@@ -10,8 +10,6 @@ import net.minecraft.server.v1_11_R1.Packet;
 import org.bukkit.craftbukkit.v1_11_R1.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 
-import java.io.IOException;
-
 abstract class VersionNMSPacket implements PacketGroup {
 
     @Override
@@ -21,14 +19,4 @@ abstract class VersionNMSPacket implements PacketGroup {
 
     abstract Packet<?> getRawPacket();
 
-    protected static <T extends Packet<?>> T writeData(T packet, PacketByteBuffer packetByteBuffer) {
-        try {
-            packet.a(packetByteBuffer);
-            return packet;
-        } catch (IOException e) {
-            // Never thrown by the implementations
-            throw new RuntimeException(e);
-        }
-    }
-
 }

nms/v1_12_r1/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-nms</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-nms-v1_12_r1</artifactId>

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/EntityLivingSpawnNMSPacket.java

@@ -62,7 +62,7 @@ class EntityLivingSpawnNMSPacket extends VersionNMSPacket {
         // Entries are deserialized and saved into a field which is not used during the re-serialization, set as empty
         packetByteBuffer.writeDataWatcherEntriesEnd();
 
-        Packet<?> rawPacket = writeData(new PacketPlayOutSpawnEntityLiving(), packetByteBuffer);
+        Packet<?> rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntityLiving());
         return new Builder(rawPacket, PacketByteBuffer.get());
     }
 

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/EntityMetadataNMSPacket.java

@@ -14,7 +14,7 @@ class EntityMetadataNMSPacket extends VersionNMSPacket {
     private final Packet<?> rawPacket;
 
     private EntityMetadataNMSPacket(PacketByteBuffer packetByteBuffer) {
-        this.rawPacket = writeData(new PacketPlayOutEntityMetadata(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityMetadata());
     }
 
     @Override

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/EntityMountNMSPacket.java

@@ -19,7 +19,7 @@ class EntityMountNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeVarInt(vehicleEntityID.getNumericID());
         packetByteBuffer.writeVarIntArray(passengerEntityID.getNumericID());
 
-        this.rawPacket = writeData(new PacketPlayOutMount(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutMount());
     }
 
     @Override

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/EntitySpawnNMSPacket.java

@@ -42,7 +42,7 @@ class EntitySpawnNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeShort(0);
         packetByteBuffer.writeShort(0);
 
-        this.rawPacket = writeData(new PacketPlayOutSpawnEntity(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntity());
     }
 
     @Override

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/EntityTeleportNMSPacket.java

@@ -31,7 +31,7 @@ class EntityTeleportNMSPacket extends VersionNMSPacket {
         // On ground
         packetByteBuffer.writeBoolean(false);
 
-        this.rawPacket = writeData(new PacketPlayOutEntityTeleport(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityTeleport());
     }
 
     @Override

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/PacketByteBuffer.java

@@ -6,25 +6,58 @@
 package me.filoghost.holographicdisplays.nms.v1_12_R1;
 
 import io.netty.buffer.Unpooled;
+import net.minecraft.server.v1_12_R1.Packet;
 import net.minecraft.server.v1_12_R1.PacketDataSerializer;
 
+import java.io.IOException;
 import java.util.UUID;
 
-class PacketByteBuffer extends PacketDataSerializer {
+class PacketByteBuffer {
 
-    private static final PacketByteBuffer INSTANCE = new PacketByteBuffer();
+    private static final ThreadLocal<PacketByteBuffer> LOCAL_INSTANCE = ThreadLocal.withInitial(PacketByteBuffer::new);
+
+    private final PacketDataSerializer serializer;
 
     static PacketByteBuffer get() {
-        INSTANCE.clear();
-        return INSTANCE;
+        PacketByteBuffer instance = LOCAL_INSTANCE.get();
+        instance.clear();
+        return instance;
     }
 
     private PacketByteBuffer() {
-        super(Unpooled.buffer());
+        this.serializer = new PacketDataSerializer(Unpooled.buffer());
+    }
+
+    int readableBytes() {
+        return serializer.readableBytes();
+    }
+
+    void readBytes(byte[] bytes) {
+        serializer.readBytes(bytes);
+    }
+
+    void writeBoolean(boolean flag) {
+        serializer.writeBoolean(flag);
+    }
+
+    void writeByte(int i) {
+        serializer.writeByte(i);
+    }
+
+    void writeShort(int i) {
+        serializer.writeShort(i);
+    }
+
+    void writeInt(int i) {
+        serializer.writeInt(i);
+    }
+
+    void writeDouble(double d) {
+        serializer.writeDouble(d);
     }
 
     void writeVarInt(int i) {
-        super.d(i);
+        serializer.d(i);
     }
 
     void writeVarIntArray(int i1) {
@@ -33,17 +66,31 @@ class PacketByteBuffer extends PacketDataSerializer {
     }
 
     void writeUUID(UUID uuid) {
-        super.a(uuid);
+        serializer.a(uuid);
     }
 
     <T> void writeDataWatcherEntry(DataWatcherKey<T> key, T value) {
-        writeByte(key.getIndex());
+        serializer.writeByte(key.getIndex());
         writeVarInt(key.getSerializerTypeID());
-        key.getSerializer().a(this, value);
+        key.getSerializer().a(serializer, value);
     }
 
     void writeDataWatcherEntriesEnd() {
-        writeByte(0xFF);
+        serializer.writeByte(0xFF);
+    }
+
+    void clear() {
+        serializer.clear();
+    }
+
+    <T extends Packet<?>> T writeDataTo(T packet) {
+        try {
+            packet.a(serializer);
+            return packet;
+        } catch (IOException e) {
+            // Never thrown by the implementations
+            throw new RuntimeException(e);
+        }
     }
 
 }

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/VersionNMSManager.java

@@ -8,6 +8,7 @@ package me.filoghost.holographicdisplays.nms.v1_12_R1;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelPipeline;
+import io.netty.channel.EventLoop;
 import me.filoghost.fcommons.logging.ErrorCollector;
 import me.filoghost.fcommons.logging.Log;
 import me.filoghost.fcommons.reflection.ReflectField;
@@ -115,8 +116,12 @@ public class VersionNMSManager implements NMSManager {
         PlayerConnection playerConnection = ((CraftPlayer) player).getHandle().playerConnection;
         NetworkManager networkManager = playerConnection.a();
         Channel channel = networkManager.channel;
+        if (channel == null) {
+            return;
+        }
+        EventLoop eventLoop = channel.eventLoop();
 
-        channel.eventLoop().execute(() -> {
+        Runnable safeModifierTask = () -> {
             if (!player.isOnline()) {
                 return;
             }
@@ -125,7 +130,13 @@ public class VersionNMSManager implements NMSManager {
             } catch (Exception e) {
                 Log.warning(NMSErrors.EXCEPTION_MODIFYING_CHANNEL_PIPELINE, e);
             }
-        });
+        };
+
+        if (eventLoop.inEventLoop()) {
+            safeModifierTask.run();
+        } else {
+            eventLoop.execute(safeModifierTask);
+        }
     }
 
 }

nms/v1_12_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_12_R1/VersionNMSPacket.java

@@ -10,8 +10,6 @@ import net.minecraft.server.v1_12_R1.Packet;
 import org.bukkit.craftbukkit.v1_12_R1.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 
-import java.io.IOException;
-
 abstract class VersionNMSPacket implements PacketGroup {
 
     @Override
@@ -21,14 +19,4 @@ abstract class VersionNMSPacket implements PacketGroup {
 
     abstract Packet<?> getRawPacket();
 
-    protected static <T extends Packet<?>> T writeData(T packet, PacketByteBuffer packetByteBuffer) {
-        try {
-            packet.a(packetByteBuffer);
-            return packet;
-        } catch (IOException e) {
-            // Never thrown by the implementations
-            throw new RuntimeException(e);
-        }
-    }
-
 }

nms/v1_13_r2/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-nms</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-nms-v1_13_r2</artifactId>

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/EntityLivingSpawnNMSPacket.java

@@ -62,7 +62,7 @@ class EntityLivingSpawnNMSPacket extends VersionNMSPacket {
         // Entries are deserialized and saved into a field which is not used during the re-serialization, set as empty
         packetByteBuffer.writeDataWatcherEntriesEnd();
 
-        Packet<?> rawPacket = writeData(new PacketPlayOutSpawnEntityLiving(), packetByteBuffer);
+        Packet<?> rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntityLiving());
         return new Builder(rawPacket, PacketByteBuffer.get());
     }
 

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/EntityMetadataNMSPacket.java

@@ -14,7 +14,7 @@ class EntityMetadataNMSPacket extends VersionNMSPacket {
     private final Packet<?> rawPacket;
 
     private EntityMetadataNMSPacket(PacketByteBuffer packetByteBuffer) {
-        this.rawPacket = writeData(new PacketPlayOutEntityMetadata(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityMetadata());
     }
 
     @Override

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/EntityMountNMSPacket.java

@@ -19,7 +19,7 @@ class EntityMountNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeVarInt(vehicleEntityID.getNumericID());
         packetByteBuffer.writeVarIntArray(passengerEntityID.getNumericID());
 
-        this.rawPacket = writeData(new PacketPlayOutMount(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutMount());
     }
 
     @Override

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/EntitySpawnNMSPacket.java

@@ -42,7 +42,7 @@ class EntitySpawnNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeShort(0);
         packetByteBuffer.writeShort(0);
 
-        this.rawPacket = writeData(new PacketPlayOutSpawnEntity(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntity());
     }
 
     @Override

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/EntityTeleportNMSPacket.java

@@ -31,7 +31,7 @@ class EntityTeleportNMSPacket extends VersionNMSPacket {
         // On ground
         packetByteBuffer.writeBoolean(false);
 
-        this.rawPacket = writeData(new PacketPlayOutEntityTeleport(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityTeleport());
     }
 
     @Override

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/PacketByteBuffer.java

@@ -6,25 +6,58 @@
 package me.filoghost.holographicdisplays.nms.v1_13_R2;
 
 import io.netty.buffer.Unpooled;
+import net.minecraft.server.v1_13_R2.Packet;
 import net.minecraft.server.v1_13_R2.PacketDataSerializer;
 
+import java.io.IOException;
 import java.util.UUID;
 
-class PacketByteBuffer extends PacketDataSerializer {
+class PacketByteBuffer {
 
-    private static final PacketByteBuffer INSTANCE = new PacketByteBuffer();
+    private static final ThreadLocal<PacketByteBuffer> LOCAL_INSTANCE = ThreadLocal.withInitial(PacketByteBuffer::new);
+
+    private final PacketDataSerializer serializer;
 
     static PacketByteBuffer get() {
-        INSTANCE.clear();
-        return INSTANCE;
+        PacketByteBuffer instance = LOCAL_INSTANCE.get();
+        instance.clear();
+        return instance;
     }
 
     private PacketByteBuffer() {
-        super(Unpooled.buffer());
+        this.serializer = new PacketDataSerializer(Unpooled.buffer());
+    }
+
+    int readableBytes() {
+        return serializer.readableBytes();
+    }
+
+    void readBytes(byte[] bytes) {
+        serializer.readBytes(bytes);
+    }
+
+    void writeBoolean(boolean flag) {
+        serializer.writeBoolean(flag);
+    }
+
+    void writeByte(int i) {
+        serializer.writeByte(i);
+    }
+
+    void writeShort(int i) {
+        serializer.writeShort(i);
+    }
+
+    void writeInt(int i) {
+        serializer.writeInt(i);
+    }
+
+    void writeDouble(double d) {
+        serializer.writeDouble(d);
     }
 
     void writeVarInt(int i) {
-        super.d(i);
+        serializer.d(i);
     }
 
     void writeVarIntArray(int i1) {
@@ -33,17 +66,31 @@ class PacketByteBuffer extends PacketDataSerializer {
     }
 
     void writeUUID(UUID uuid) {
-        super.a(uuid);
+        serializer.a(uuid);
     }
 
     <T> void writeDataWatcherEntry(DataWatcherKey<T> key, T value) {
-        writeByte(key.getIndex());
+        serializer.writeByte(key.getIndex());
         writeVarInt(key.getSerializerTypeID());
-        key.getSerializer().a(this, value);
+        key.getSerializer().a(serializer, value);
     }
 
     void writeDataWatcherEntriesEnd() {
-        writeByte(0xFF);
+        serializer.writeByte(0xFF);
+    }
+
+    void clear() {
+        serializer.clear();
+    }
+
+    <T extends Packet<?>> T writeDataTo(T packet) {
+        try {
+            packet.a(serializer);
+            return packet;
+        } catch (IOException e) {
+            // Never thrown by the implementations
+            throw new RuntimeException(e);
+        }
     }
 
 }

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/VersionNMSManager.java

@@ -8,6 +8,7 @@ package me.filoghost.holographicdisplays.nms.v1_13_R2;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelPipeline;
+import io.netty.channel.EventLoop;
 import me.filoghost.fcommons.logging.ErrorCollector;
 import me.filoghost.fcommons.logging.Log;
 import me.filoghost.fcommons.reflection.ReflectField;
@@ -115,8 +116,12 @@ public class VersionNMSManager implements NMSManager {
         PlayerConnection playerConnection = ((CraftPlayer) player).getHandle().playerConnection;
         NetworkManager networkManager = playerConnection.a();
         Channel channel = networkManager.channel;
+        if (channel == null) {
+            return;
+        }
+        EventLoop eventLoop = channel.eventLoop();
 
-        channel.eventLoop().execute(() -> {
+        Runnable safeModifierTask = () -> {
             if (!player.isOnline()) {
                 return;
             }
@@ -125,7 +130,13 @@ public class VersionNMSManager implements NMSManager {
             } catch (Exception e) {
                 Log.warning(NMSErrors.EXCEPTION_MODIFYING_CHANNEL_PIPELINE, e);
             }
-        });
+        };
+
+        if (eventLoop.inEventLoop()) {
+            safeModifierTask.run();
+        } else {
+            eventLoop.execute(safeModifierTask);
+        }
     }
 
 }

nms/v1_13_r2/src/main/java/me/filoghost/holographicdisplays/nms/v1_13_R2/VersionNMSPacket.java

@@ -10,8 +10,6 @@ import net.minecraft.server.v1_13_R2.Packet;
 import org.bukkit.craftbukkit.v1_13_R2.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 
-import java.io.IOException;
-
 abstract class VersionNMSPacket implements PacketGroup {
 
     @Override
@@ -21,14 +19,4 @@ abstract class VersionNMSPacket implements PacketGroup {
 
     abstract Packet<?> getRawPacket();
 
-    protected static <T extends Packet<?>> T writeData(T packet, PacketByteBuffer packetByteBuffer) {
-        try {
-            packet.a(packetByteBuffer);
-            return packet;
-        } catch (IOException e) {
-            // Never thrown by the implementations
-            throw new RuntimeException(e);
-        }
-    }
-
 }

nms/v1_14_r1/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-nms</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-nms-v1_14_r1</artifactId>

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/EntityLivingSpawnNMSPacket.java

@@ -62,7 +62,7 @@ class EntityLivingSpawnNMSPacket extends VersionNMSPacket {
         // Entries are deserialized and saved into a field which is not used during the re-serialization, set as empty
         packetByteBuffer.writeDataWatcherEntriesEnd();
 
-        Packet<?> rawPacket = writeData(new PacketPlayOutSpawnEntityLiving(), packetByteBuffer);
+        Packet<?> rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntityLiving());
         return new Builder(rawPacket, PacketByteBuffer.get());
     }
 

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/EntityMetadataNMSPacket.java

@@ -14,7 +14,7 @@ class EntityMetadataNMSPacket extends VersionNMSPacket {
     private final Packet<?> rawPacket;
 
     private EntityMetadataNMSPacket(PacketByteBuffer packetByteBuffer) {
-        this.rawPacket = writeData(new PacketPlayOutEntityMetadata(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityMetadata());
     }
 
     @Override

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/EntityMountNMSPacket.java

@@ -19,7 +19,7 @@ class EntityMountNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeVarInt(vehicleEntityID.getNumericID());
         packetByteBuffer.writeVarIntArray(passengerEntityID.getNumericID());
 
-        this.rawPacket = writeData(new PacketPlayOutMount(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutMount());
     }
 
     @Override

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/EntitySpawnNMSPacket.java

@@ -42,7 +42,7 @@ class EntitySpawnNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeShort(0);
         packetByteBuffer.writeShort(0);
 
-        this.rawPacket = writeData(new PacketPlayOutSpawnEntity(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntity());
     }
 
     @Override

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/EntityTeleportNMSPacket.java

@@ -31,7 +31,7 @@ class EntityTeleportNMSPacket extends VersionNMSPacket {
         // On ground
         packetByteBuffer.writeBoolean(false);
 
-        this.rawPacket = writeData(new PacketPlayOutEntityTeleport(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityTeleport());
     }
 
     @Override

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/PacketByteBuffer.java

@@ -6,25 +6,58 @@
 package me.filoghost.holographicdisplays.nms.v1_14_R1;
 
 import io.netty.buffer.Unpooled;
+import net.minecraft.server.v1_14_R1.Packet;
 import net.minecraft.server.v1_14_R1.PacketDataSerializer;
 
+import java.io.IOException;
 import java.util.UUID;
 
-class PacketByteBuffer extends PacketDataSerializer {
+class PacketByteBuffer {
 
-    private static final PacketByteBuffer INSTANCE = new PacketByteBuffer();
+    private static final ThreadLocal<PacketByteBuffer> LOCAL_INSTANCE = ThreadLocal.withInitial(PacketByteBuffer::new);
+
+    private final PacketDataSerializer serializer;
 
     static PacketByteBuffer get() {
-        INSTANCE.clear();
-        return INSTANCE;
+        PacketByteBuffer instance = LOCAL_INSTANCE.get();
+        instance.clear();
+        return instance;
     }
 
     private PacketByteBuffer() {
-        super(Unpooled.buffer());
+        this.serializer = new PacketDataSerializer(Unpooled.buffer());
+    }
+
+    int readableBytes() {
+        return serializer.readableBytes();
+    }
+
+    void readBytes(byte[] bytes) {
+        serializer.readBytes(bytes);
+    }
+
+    void writeBoolean(boolean flag) {
+        serializer.writeBoolean(flag);
+    }
+
+    void writeByte(int i) {
+        serializer.writeByte(i);
+    }
+
+    void writeShort(int i) {
+        serializer.writeShort(i);
+    }
+
+    void writeInt(int i) {
+        serializer.writeInt(i);
+    }
+
+    void writeDouble(double d) {
+        serializer.writeDouble(d);
     }
 
     void writeVarInt(int i) {
-        super.d(i);
+        serializer.d(i);
     }
 
     void writeVarIntArray(int i1) {
@@ -33,17 +66,31 @@ class PacketByteBuffer extends PacketDataSerializer {
     }
 
     void writeUUID(UUID uuid) {
-        super.a(uuid);
+        serializer.a(uuid);
     }
 
     <T> void writeDataWatcherEntry(DataWatcherKey<T> key, T value) {
-        writeByte(key.getIndex());
+        serializer.writeByte(key.getIndex());
         writeVarInt(key.getSerializerTypeID());
-        key.getSerializer().a(this, value);
+        key.getSerializer().a(serializer, value);
     }
 
     void writeDataWatcherEntriesEnd() {
-        writeByte(0xFF);
+        serializer.writeByte(0xFF);
+    }
+
+    void clear() {
+        serializer.clear();
+    }
+
+    <T extends Packet<?>> T writeDataTo(T packet) {
+        try {
+            packet.a(serializer);
+            return packet;
+        } catch (IOException e) {
+            // Never thrown by the implementations
+            throw new RuntimeException(e);
+        }
     }
 
 }

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/VersionNMSManager.java

@@ -8,6 +8,7 @@ package me.filoghost.holographicdisplays.nms.v1_14_R1;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelPipeline;
+import io.netty.channel.EventLoop;
 import me.filoghost.fcommons.logging.ErrorCollector;
 import me.filoghost.fcommons.logging.Log;
 import me.filoghost.fcommons.reflection.ReflectField;
@@ -100,8 +101,12 @@ public class VersionNMSManager implements NMSManager {
         PlayerConnection playerConnection = ((CraftPlayer) player).getHandle().playerConnection;
         NetworkManager networkManager = playerConnection.a();
         Channel channel = networkManager.channel;
+        if (channel == null) {
+            return;
+        }
+        EventLoop eventLoop = channel.eventLoop();
 
-        channel.eventLoop().execute(() -> {
+        Runnable safeModifierTask = () -> {
             if (!player.isOnline()) {
                 return;
             }
@@ -110,7 +115,13 @@ public class VersionNMSManager implements NMSManager {
             } catch (Exception e) {
                 Log.warning(NMSErrors.EXCEPTION_MODIFYING_CHANNEL_PIPELINE, e);
             }
-        });
+        };
+
+        if (eventLoop.inEventLoop()) {
+            safeModifierTask.run();
+        } else {
+            eventLoop.execute(safeModifierTask);
+        }
     }
 
 }

nms/v1_14_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_14_R1/VersionNMSPacket.java

@@ -10,8 +10,6 @@ import net.minecraft.server.v1_14_R1.Packet;
 import org.bukkit.craftbukkit.v1_14_R1.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 
-import java.io.IOException;
-
 abstract class VersionNMSPacket implements PacketGroup {
 
     @Override
@@ -21,14 +19,4 @@ abstract class VersionNMSPacket implements PacketGroup {
 
     abstract Packet<?> getRawPacket();
 
-    protected static <T extends Packet<?>> T writeData(T packet, PacketByteBuffer packetByteBuffer) {
-        try {
-            packet.a(packetByteBuffer);
-            return packet;
-        } catch (IOException e) {
-            // Never thrown by the implementations
-            throw new RuntimeException(e);
-        }
-    }
-
 }

nms/v1_15_r1/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>me.filoghost.holographicdisplays</groupId>
         <artifactId>holographicdisplays-nms</artifactId>
-        <version>3.0.0</version>
+        <version>3.0.5-SNAPSHOT</version>
     </parent>
 
     <artifactId>holographicdisplays-nms-v1_15_r1</artifactId>

nms/v1_15_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_15_R1/EntityLivingSpawnNMSPacket.java

@@ -38,7 +38,7 @@ class EntityLivingSpawnNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeShort(0);
         packetByteBuffer.writeShort(0);
 
-        this.rawPacket = writeData(new PacketPlayOutSpawnEntityLiving(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntityLiving());
     }
 
     @Override

nms/v1_15_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_15_R1/EntityMetadataNMSPacket.java

@@ -14,7 +14,7 @@ class EntityMetadataNMSPacket extends VersionNMSPacket {
     private final Packet<?> rawPacket;
 
     private EntityMetadataNMSPacket(PacketByteBuffer packetByteBuffer) {
-        this.rawPacket = writeData(new PacketPlayOutEntityMetadata(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutEntityMetadata());
     }
 
     @Override

nms/v1_15_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_15_R1/EntityMountNMSPacket.java

@@ -19,7 +19,7 @@ class EntityMountNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeVarInt(vehicleEntityID.getNumericID());
         packetByteBuffer.writeVarIntArray(passengerEntityID.getNumericID());
 
-        this.rawPacket = writeData(new PacketPlayOutMount(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutMount());
     }
 
     @Override

nms/v1_15_r1/src/main/java/me/filoghost/holographicdisplays/nms/v1_15_R1/EntitySpawnNMSPacket.java

@@ -42,7 +42,7 @@ class EntitySpawnNMSPacket extends VersionNMSPacket {
         packetByteBuffer.writeShort(0);
         packetByteBuffer.writeShort(0);
 
-        this.rawPacket = writeData(new PacketPlayOutSpawnEntity(), packetByteBuffer);
+        this.rawPacket = packetByteBuffer.writeDataTo(new PacketPlayOutSpawnEntity());
     }
 
     @Override