add java 8 support (fixes #33), change folia support, restructure project

README.md

@@ -1,11 +1,10 @@
 # ZNPCsPlus
-[ZNPCsPlus](https://www.spigotmc.org/resources/znpcsplus.109380/) is an unofficial fork of the popular NPC plugin ZNPCs written with the Spigot/Bukkit API originally made by 
+[ZNPCsPlus](https://www.spigotmc.org/resources/znpcsplus.109380/) is an remake of the popular NPC plugin ZNPCs written with the Spigot/Bukkit API originally made by 
-gonalez/ZNetwork. This fork was made because the original maintainer of the plugin decided to announce that he was 
+gonalez/ZNetwork. This project was originally started because the maintainer of ZNPCs decided to announce that he was 
-[dropping support for the plugin](https://media.discordapp.net/attachments/1093914615873806477/1098409384855474237/znpc.png) 
+[dropping support for the plugin](https://media.discordapp.net/attachments/1093914615873806477/1098409384855474237/znpc.png).
-in the original project's [official discord server](https://discord.com/invite/RhNMH4T).
 
 ### Dependencies
-- Java 17
+- Java 8
 - Spigot 1.8 - 1.19.4
 - PlaceholderAPI (OPTIONAL)
 
@@ -15,7 +14,10 @@ If you're using a Minecraft version that rejects Java 17 use the `-DPaper.Ignore
 This fork makes several improvements over the original including:
 - More performance-conscious code
 - Latest version support (1.19.4)
-- Fixes for long-running issues of the original plugin (ones that the original maintainer refused to even acknowledge)
+- Fixes for long-running issues of the original plugin
+- Better stability
+- Support for multiple different storage options (WIP)
+- Better command system (WIP)
 
 ## Found a bug?
 Open an issue in the GitHub [issue tracker](https://github.com/Pyrbu/ZNPCsPlus/issues)

api/build.gradle

@@ -1,4 +1,5 @@
 plugins {
+    id "java"
     id "maven-publish"
 }
 

api/src/main/java/lol/pyr/znpcsplus/api/npc/NPCType.java

@@ -86,7 +86,7 @@ public class NPCType {
         }
 
         public Builder addProperties(EntityProperty<?>... properties) {
-            allowedProperties.addAll(List.of(properties));
+            allowedProperties.addAll(Arrays.asList(properties));
             return this;
         }
 
@@ -108,7 +108,7 @@ public class NPCType {
                 if (PacketEvents.getAPI().getServerManager().getVersion().isNewerThanOrEquals(ServerVersion.V_1_9))
                     allowedProperties.add(EntityProperty.GLOW);
             }
-            return new NPCType(name, type, hologramOffset, Set.copyOf(allowedProperties));
+            return new NPCType(name, type, hologramOffset, new HashSet<>(allowedProperties));
         }
     }
 }

build.gradle

@@ -1,27 +1,11 @@
-plugins {
+subprojects {
-    id "java"
-    id "com.github.johnrengelman.shadow" version "8.1.1"
-    id "xyz.jpenilla.run-paper" version "2.0.1"
-}
-
-dependencies {
-    implementation project(path: ":spigot", configuration: "shadow")
-    implementation project(":api")
-    implementation project(":folia")
-}
-
-runServer {
-    minecraftVersion "1.19.4"
-}
-
-allprojects {
     apply plugin: "java"
 
     group "lol.pyr"
     version "2.0.0"
 
     compileJava {
-        options.release.set(17)
+        options.release.set(8)
     }
 
     repositories {
@@ -32,6 +16,9 @@ allprojects {
         maven {
             url "https://repo.codemc.io/repository/maven-snapshots/"
         }
+        maven {
+            url "https://libraries.minecraft.net"
+        }
         maven {
             url "https://repo.papermc.io/repository/maven-public/"
         }
@@ -46,6 +33,3 @@ allprojects {
         }
     }
 }
-
-tasks.assemble.dependsOn shadowJar
-tasks.compileJava.dependsOn clean

folia/build.gradle

@@ -1,3 +0,0 @@
-dependencies {
-    compileOnly "dev.folia:folia-api:1.19.4-R0.1-SNAPSHOT"
-}

folia/src/main/java/lol/pyr/znpcsplus/scheduling/FoliaScheduler.java

@@ -1,27 +0,0 @@
-package lol.pyr.znpcsplus.scheduling;
-
-import org.bukkit.Bukkit;
-import org.bukkit.plugin.Plugin;
-
-import java.util.concurrent.TimeUnit;
-
-public class FoliaScheduler extends TaskScheduler {
-    public FoliaScheduler(Plugin plugin) {
-        super(plugin);
-    }
-
-    @Override
-    public void runAsync(Runnable runnable) {
-        Bukkit.getAsyncScheduler().runNow(plugin, task -> runnable.run());
-    }
-
-    @Override
-    public void runLaterAsync(Runnable runnable, long ticks) {
-        Bukkit.getAsyncScheduler().runDelayed(plugin, task -> runnable.run(), ticks * 50, TimeUnit.MILLISECONDS);
-    }
-
-    @Override
-    public void runDelayedTimerAsync(Runnable runnable, long delay, long ticks) {
-        Bukkit.getAsyncScheduler().runAtFixedRate(plugin, task -> runnable.run(), delay * 50, ticks * 50, TimeUnit.MILLISECONDS);
-    }
-}

settings.gradle

@@ -1,3 +1,3 @@
 rootProject.name = "ZNPCsPlus"
 
-include "api", "spigot", "folia"
+include "api", "spigot"

spigot/build.gradle

@@ -1,12 +1,22 @@
 plugins {
+    id "java"
     id "com.github.johnrengelman.shadow" version "8.1.1"
+    id "xyz.jpenilla.run-paper" version "2.0.1"
+}
+
+runServer {
+    minecraftVersion "1.19.4"
+}
+
+processResources {
+    expand("version": version)
 }
 
 dependencies {
     compileOnly "org.spigotmc:spigot-api:1.19.4-R0.1-SNAPSHOT"
     compileOnly "me.clip:placeholderapi:2.11.1"
 
-    compileOnly "com.mojang:authlib:3.4.40"
+    compileOnly "com.mojang:authlib:1.5.21"
     compileOnly "com.mojang:datafixerupper:4.0.26"
 
     implementation "commons-io:commons-io:2.11.0"
@@ -19,13 +29,13 @@ dependencies {
     implementation "space.arim.dazzleconf:dazzleconf-ext-snakeyaml:1.2.1"
 
     implementation "lol.pyr:director-adventure:2.0.1"
-
+    implementation project(":api")
-    compileOnly project(":api")
-    compileOnly project(":folia")
 }
 
 shadowJar {
+    archivesBaseName = "ZNPCsPlus"
     archiveClassifier.set ""
+
     relocate "org.bstats", "lol.pyr.znpcsplus.lib.bstats"
     relocate "org.apache.commons.io", "lol.pyr.znpcsplus.lib.commonsio"
     relocate "me.robertlit.spigotresources", "lol.pyr.znpcsplus.lib.spigotresources"
@@ -43,3 +53,5 @@ shadowJar {
     relocate "lol.pyr.director", "lol.pyr.znpcsplus.lib.command"
     minimize()
 }
+
+tasks.assemble.dependsOn shadowJar

spigot/src/main/java/io/github/znetworkw/znpcservers/reflection/ReflectionBuilder.java

@@ -15,6 +15,11 @@ public class ReflectionBuilder {
     private Class<?> expectType;
     private boolean strict = true;
 
+    public ReflectionBuilder(Class<?> clazz) {
+        this("");
+        withClassName(clazz);
+    }
+
     public ReflectionBuilder(String reflectionPackage) {
         this(reflectionPackage, "", "", null);
     }

spigot/src/main/java/io/github/znetworkw/znpcservers/reflection/Reflections.java

@@ -5,40 +5,92 @@ import io.github.znetworkw.znpcservers.reflection.types.ClassReflection;
 import io.github.znetworkw.znpcservers.reflection.types.FieldReflection;
 import io.github.znetworkw.znpcservers.reflection.types.MethodReflection;
 import io.github.znetworkw.znpcservers.utility.Utils;
+import lol.pyr.znpcsplus.util.FoliaUtil;
+import org.bukkit.Bukkit;
+import org.bukkit.plugin.Plugin;
 
 import java.lang.reflect.Method;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
 
 /**
  * Class containing all of the lazy-loaded reflections that the plugin
  * uses to accessinaccessible things from the server jar.
  */
 public final class Reflections {
-    public static final Class<?> ENTITY_CLASS = new ClassReflection(new ReflectionBuilder(ReflectionPackage.ENTITY)
+    public static final Class<?> ENTITY_CLASS = new ClassReflection(
+            new ReflectionBuilder(ReflectionPackage.ENTITY)
                     .withClassName("Entity")).get();
 
-    public static final Class<?> ENTITY_HUMAN_CLASS = new ClassReflection(new ReflectionBuilder(ReflectionPackage.ENTITY)
+    public static final Class<?> ENTITY_HUMAN_CLASS = new ClassReflection(
+            new ReflectionBuilder(ReflectionPackage.ENTITY)
                     .withSubClass("player")
                     .withClassName("EntityHuman")).get();
 
-    public static final ReflectionLazyLoader<Method> GET_PROFILE_METHOD = new MethodReflection(new ReflectionBuilder(ReflectionPackage.ENTITY)
+    public static final ReflectionLazyLoader<Method> GET_PROFILE_METHOD = new MethodReflection(
+            new ReflectionBuilder(ReflectionPackage.ENTITY)
                     .withClassName(ENTITY_HUMAN_CLASS)
                     .withExpectResult(GameProfile.class));
 
-    public static final ReflectionLazyLoader<Method> GET_HANDLE_PLAYER_METHOD = new MethodReflection(new ReflectionBuilder(ReflectionPackage.BUKKIT)
+    public static final ReflectionLazyLoader<Method> GET_HANDLE_PLAYER_METHOD = new MethodReflection(
+            new ReflectionBuilder(ReflectionPackage.BUKKIT)
                     .withClassName("entity.CraftPlayer").withClassName("entity.CraftHumanEntity")
                     .withMethodName("getHandle"));
 
-    public static final FieldReflection.ValueModifier<Integer> ENTITY_ID_MODIFIER = new FieldReflection(new ReflectionBuilder(ReflectionPackage.ENTITY)
+    public static final FieldReflection.ValueModifier<Integer> ENTITY_ID_MODIFIER = new FieldReflection(
+            new ReflectionBuilder(ReflectionPackage.ENTITY)
                     .withClassName(ENTITY_CLASS)
                     .withFieldName("entityCount")
                     .setStrict(!Utils.versionNewer(14))).staticValueModifier(int.class);
 
-    public static final ReflectionLazyLoader<AtomicInteger> ATOMIC_ENTITY_ID_FIELD = new FieldReflection(new ReflectionBuilder(ReflectionPackage.ENTITY)
+    public static final ReflectionLazyLoader<AtomicInteger> ATOMIC_ENTITY_ID_FIELD = new FieldReflection(
+            new ReflectionBuilder(ReflectionPackage.ENTITY)
                     .withClassName(ENTITY_CLASS)
                     .withFieldName("entityCount")
                     .withFieldName("d")
                     .withFieldName("c")
                     .withExpectResult(AtomicInteger.class)
                     .setStrict(Utils.versionNewer(14))).staticValueLoader(AtomicInteger.class);
+
+    public static final Class<?> ASYNC_SCHEDULER_CLASS = new ClassReflection(
+            new ReflectionBuilder("io.papermc.paper.threadedregions.scheduler")
+                    .withClassName("AsyncScheduler")
+                    .setStrict(FoliaUtil.isFolia())).get();
+
+    public static final Class<?> SCHEDULED_TASK_CLASS = new ClassReflection(
+            new ReflectionBuilder("io.papermc.paper.threadedregions.scheduler")
+                    .withClassName("ScheduledTask")
+                    .setStrict(FoliaUtil.isFolia())).get();
+
+    public static final ReflectionLazyLoader<Method> FOLIA_GET_ASYNC_SCHEDULER = new MethodReflection(
+            new ReflectionBuilder(Bukkit.class)
+                    .withMethodName("getAsyncScheduler")
+                    .withExpectResult(ASYNC_SCHEDULER_CLASS)
+                    .setStrict(FoliaUtil.isFolia()));
+
+    public static final ReflectionLazyLoader<Method> FOLIA_RUN_NOW = new MethodReflection(
+            new ReflectionBuilder(ASYNC_SCHEDULER_CLASS)
+                    .withMethodName("runNow")
+                    .withParameterTypes(Plugin.class, Consumer.class)
+                    .withExpectResult(SCHEDULED_TASK_CLASS)
+                    .setStrict(FoliaUtil.isFolia()));
+
+    public static final ReflectionLazyLoader<Method> FOLIA_RUN_DELAYED = new MethodReflection(
+            new ReflectionBuilder(ASYNC_SCHEDULER_CLASS)
+                    .withMethodName("runDelayed")
+                    .withParameterTypes(Plugin.class, Consumer.class, long.class, TimeUnit.class)
+                    .withExpectResult(SCHEDULED_TASK_CLASS)
+                    .setStrict(FoliaUtil.isFolia()));
+
+    public static final ReflectionLazyLoader<Method> FOLIA_RUN_AT_FIXED_RATE = new MethodReflection(
+            new ReflectionBuilder(ASYNC_SCHEDULER_CLASS)
+                    .withMethodName("runAtFixedRate")
+                    .withParameterTypes(Plugin.class, Consumer.class, long.class, long.class, TimeUnit.class)
+                    .withExpectResult(SCHEDULED_TASK_CLASS)
+                    .setStrict(FoliaUtil.isFolia()));
 }
+
+// Bukkit.getAsyncScheduler().runNow(plugin, task -> runnable.run());
+// Bukkit.getAsyncScheduler().runDelayed(plugin, task -> runnable.run(), ticks * 50, TimeUnit.MILLISECONDS);
+// Bukkit.getAsyncScheduler().runAtFixedRate(plugin, task -> runnable.run(), delay * 50, ticks * 50, TimeUnit.MILLISECONDS);

spigot/src/main/java/lol/pyr/znpcsplus/hologram/Hologram.java

@@ -1,14 +1,14 @@
 package lol.pyr.znpcsplus.hologram;
 
 import lol.pyr.znpcsplus.config.Configs;
-import lol.pyr.znpcsplus.util.ZLocation;
 import lol.pyr.znpcsplus.util.Viewable;
+import lol.pyr.znpcsplus.util.ZLocation;
 import net.kyori.adventure.text.Component;
 import org.bukkit.entity.Player;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
-import java.util.Set;
 
 public class Hologram extends Viewable implements lol.pyr.znpcsplus.api.hologram.Hologram {
     private ZLocation location;
@@ -70,7 +70,7 @@ public class Hologram extends Viewable implements lol.pyr.znpcsplus.api.hologram
         final double lineSpacing = Configs.config().lineSpacing();
         double height = location.getY() + lines.size() * lineSpacing;
         for (HologramLine line : lines) {
-            line.setLocation(location.withY(height), line == newLine ? Set.of() : getViewers());
+            line.setLocation(location.withY(height), line == newLine ? Collections.emptySet() : getViewers());
             height -= lineSpacing;
         }
     }

spigot/src/main/java/lol/pyr/znpcsplus/metadata/MetadataFactory.java

@@ -48,7 +48,7 @@ public interface MetadataFactory {
         throw new RuntimeException("Unsupported version!");
     }
 
-    private static Map<ServerVersion, LazyLoader<? extends MetadataFactory>> buildFactoryMap() {
+    static Map<ServerVersion, LazyLoader<? extends MetadataFactory>> buildFactoryMap() {
         HashMap<ServerVersion, LazyLoader<? extends MetadataFactory>> map = new HashMap<>();
         map.put(ServerVersion.V_1_8, LazyLoader.of(V1_8Factory::new));
         map.put(ServerVersion.V_1_9, LazyLoader.of(V1_9Factory::new));

spigot/src/main/java/lol/pyr/znpcsplus/metadata/V1_13Factory.java

@@ -3,16 +3,16 @@ package lol.pyr.znpcsplus.metadata;
 import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
 import com.github.retrooper.packetevents.protocol.entity.data.EntityDataTypes;
 import com.github.retrooper.packetevents.util.adventure.AdventureSerializer;
+import lol.pyr.znpcsplus.util.list.ListUtil;
 import net.kyori.adventure.text.Component;
 
 import java.util.Collection;
-import java.util.List;
 import java.util.Optional;
 
 public class V1_13Factory extends V1_9Factory {
     @Override
     public Collection<EntityData> name(Component name) {
-        return List.of(
+        return ListUtil.immutableList(
                 new EntityData(2, EntityDataTypes.OPTIONAL_COMPONENT, Optional.of(AdventureSerializer.getGsonSerializer().serialize(name))),
                 new EntityData(3, EntityDataTypes.BOOLEAN, true)
         );

spigot/src/main/java/lol/pyr/znpcsplus/metadata/V1_8Factory.java

@@ -3,10 +3,10 @@ package lol.pyr.znpcsplus.metadata;
 import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
 import com.github.retrooper.packetevents.protocol.entity.data.EntityDataTypes;
 import com.github.retrooper.packetevents.util.adventure.AdventureSerializer;
+import lol.pyr.znpcsplus.util.list.ListUtil;
 import net.kyori.adventure.text.Component;
 
 import java.util.Collection;
-import java.util.List;
 
 public class V1_8Factory implements MetadataFactory {
     @Override
@@ -21,7 +21,7 @@ public class V1_8Factory implements MetadataFactory {
 
     @Override
     public Collection<EntityData> name(Component name) {
-        return List.of(
+        return ListUtil.immutableList(
                 new EntityData(2, EntityDataTypes.STRING, AdventureSerializer.getGsonSerializer().serialize(name)),
                 new EntityData(3, EntityDataTypes.BYTE, 1)
         );

spigot/src/main/java/lol/pyr/znpcsplus/metadata/V1_9Factory.java

@@ -3,10 +3,10 @@ package lol.pyr.znpcsplus.metadata;
 import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
 import com.github.retrooper.packetevents.protocol.entity.data.EntityDataTypes;
 import com.github.retrooper.packetevents.util.adventure.AdventureSerializer;
+import lol.pyr.znpcsplus.util.list.ListUtil;
 import net.kyori.adventure.text.Component;
 
 import java.util.Collection;
-import java.util.List;
 
 public class V1_9Factory extends V1_8Factory {
     @Override
@@ -21,7 +21,7 @@ public class V1_9Factory extends V1_8Factory {
 
     @Override
     public Collection<EntityData> name(Component name) {
-        return List.of(
+        return ListUtil.immutableList(
                 new EntityData(2, EntityDataTypes.STRING, AdventureSerializer.getGsonSerializer().serialize(name)),
                 new EntityData(3, EntityDataTypes.BOOLEAN, true)
         );

spigot/src/main/java/lol/pyr/znpcsplus/packets/PacketFactory.java

@@ -43,7 +43,7 @@ public interface PacketFactory {
         throw new RuntimeException("Unsupported version!");
     }
 
-    private static Map<ServerVersion, LazyLoader<? extends PacketFactory>> buildFactoryMap() {
+    static Map<ServerVersion, LazyLoader<? extends PacketFactory>> buildFactoryMap() {
         HashMap<ServerVersion, LazyLoader<? extends PacketFactory>> map = new HashMap<>();
         map.put(ServerVersion.V_1_8, LazyLoader.of(V1_8Factory::new));
         map.put(ServerVersion.V_1_9, LazyLoader.of(V1_9Factory::new));

spigot/src/main/java/lol/pyr/znpcsplus/packets/V1_8Factory.java

@@ -22,6 +22,7 @@ import net.kyori.adventure.text.format.NamedTextColor;
 import org.bukkit.entity.Player;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
@@ -33,7 +34,7 @@ public class V1_8Factory implements PacketFactory {
             createTeam(player, entity, properties);
             ZLocation location = entity.getLocation();
             sendPacket(player, new WrapperPlayServerSpawnPlayer(entity.getEntityId(),
-                    entity.getUuid(), location.toVector3d(), location.getYaw(), location.getPitch(), List.of()));
+                    entity.getUuid(), location.toVector3d(), location.getYaw(), location.getPitch(), Collections.emptyList()));
             sendAllMetadata(player, entity, properties);
             ZNPCsPlus.SCHEDULER.runLaterAsync(() -> removeTabPlayer(player, entity), 60);
         });
@@ -46,7 +47,7 @@ public class V1_8Factory implements PacketFactory {
         ClientVersion clientVersion = PacketEvents.getAPI().getServerManager().getVersion().toClientVersion();
         sendPacket(player, type.getLegacyId(clientVersion) == -1 ?
                 new WrapperPlayServerSpawnLivingEntity(entity.getEntityId(), entity.getUuid(), type, location.toVector3d(),
-                        location.getYaw(), location.getPitch(), location.getPitch(), new Vector3d(), List.of()) :
+                        location.getYaw(), location.getPitch(), location.getPitch(), new Vector3d(), Collections.emptyList()) :
                 new WrapperPlayServerSpawnEntity(entity.getEntityId(), Optional.of(entity.getUuid()), entity.getType(), location.toVector3d(),
                         location.getPitch(), location.getYaw(), location.getYaw(), 0, Optional.empty()));
         sendAllMetadata(player, entity, properties);

spigot/src/main/java/lol/pyr/znpcsplus/scheduling/FoliaScheduler.java

@@ -0,0 +1,48 @@
+package lol.pyr.znpcsplus.scheduling;
+
+import io.github.znetworkw.znpcservers.reflection.Reflections;
+import org.bukkit.plugin.Plugin;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+public class FoliaScheduler extends TaskScheduler {
+    public FoliaScheduler(Plugin plugin) {
+        super(plugin);
+    }
+
+    @Override
+    public void runAsync(Runnable runnable) {
+        try {
+            Object scheduler = Reflections.FOLIA_GET_ASYNC_SCHEDULER.get().invoke(null);
+            Reflections.FOLIA_RUN_NOW.get().invoke(scheduler, plugin, (Consumer<Object>) o -> runnable.run());
+        } catch (IllegalAccessException | InvocationTargetException e) {
+            throw new RuntimeException(e);
+        }
+        // Bukkit.getAsyncScheduler().runNow(plugin, task -> runnable.run());
+    }
+
+    @Override
+    public void runLaterAsync(Runnable runnable, long ticks) {
+        try {
+            Object scheduler = Reflections.FOLIA_GET_ASYNC_SCHEDULER.get().invoke(null);
+            Reflections.FOLIA_RUN_DELAYED.get().invoke(scheduler, plugin, (Consumer<Object>) o -> runnable.run(), ticks * 50, TimeUnit.MILLISECONDS);
+        } catch (IllegalAccessException | InvocationTargetException e) {
+            throw new RuntimeException(e);
+        }
+        // Bukkit.getAsyncScheduler().runDelayed(plugin, task -> runnable.run(), ticks * 50, TimeUnit.MILLISECONDS);
+    }
+
+    @Override
+    public void runDelayedTimerAsync(Runnable runnable, long delay, long ticks) {
+        try {
+            Object scheduler = Reflections.FOLIA_GET_ASYNC_SCHEDULER.get().invoke(null);
+            Reflections.FOLIA_RUN_AT_FIXED_RATE.get().invoke(scheduler, plugin, (Consumer<Object>) o -> runnable.run(), delay * 50, ticks * 50, TimeUnit.MILLISECONDS);
+        } catch (IllegalAccessException | InvocationTargetException e) {
+            throw new RuntimeException(e);
+        }
+        // Bukkit.getAsyncScheduler().runAtFixedRate(plugin, task -> runnable.run(), delay * 50, ticks * 50, TimeUnit.MILLISECONDS);
+    }
+}
+

spigot/src/main/java/lol/pyr/znpcsplus/skin/Skin.java

@@ -5,9 +5,11 @@ import com.github.retrooper.packetevents.protocol.player.UserProfile;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.mojang.authlib.properties.PropertyMap;
+import lol.pyr.znpcsplus.util.list.ListUtil;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 public class Skin {
     private final long timestamp = System.currentTimeMillis();
@@ -18,13 +20,13 @@ public class Skin {
     }
 
     public Skin(TextureProperty... properties) {
-        this.properties.addAll(List.of(properties));
+        this.properties.addAll(ListUtil.immutableList(properties));
     }
 
     public Skin(PropertyMap properties) {
         this.properties.addAll(properties.values().stream()
                 .map(property -> new TextureProperty(property.getName(), property.getValue(), property.getSignature()))
-                .toList());
+                .collect(Collectors.toList()));
     }
 
     public Skin(JsonObject obj) {

spigot/src/main/java/lol/pyr/znpcsplus/util/FoliaUtil.java

@@ -1,7 +1,9 @@
 package lol.pyr.znpcsplus.util;
 
 public class FoliaUtil {
+    private static final Boolean FOLIA = isFolia();
     public static boolean isFolia() {
+        if (FOLIA != null) return FOLIA;
         try {
             Class.forName("io.papermc.paper.threadedregions.RegionizedServer");
             return true;

spigot/src/main/java/lol/pyr/znpcsplus/util/list/ArrayIterator.java

@@ -0,0 +1,62 @@
+package lol.pyr.znpcsplus.util.list;
+
+import java.util.Iterator;
+import java.util.ListIterator;
+
+public class ArrayIterator<T> implements Iterator<T>, ListIterator<T> {
+    private final T[] array;
+    private int index = 0;
+
+    public ArrayIterator(T[] array) {
+        this.array = array;
+    }
+
+    @Override
+    public boolean hasNext() {
+        return array.length > index;
+    }
+
+    @Override
+    public T next() {
+        return array[index++];
+    }
+
+    private boolean inBounds(int index) {
+        return index >= 0 && index < array.length;
+    }
+
+    @Override
+    public boolean hasPrevious() {
+        return inBounds(index - 1);
+    }
+
+    @Override
+    public T previous() {
+        return array[--index];
+    }
+
+    @Override
+    public int nextIndex() {
+        return index + 1;
+    }
+
+    @Override
+    public int previousIndex() {
+        return index - 1;
+    }
+
+    @Override
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void set(T t) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void add(T t) {
+        throw new UnsupportedOperationException();
+    }
+}

spigot/src/main/java/lol/pyr/znpcsplus/util/list/ImmutableArrayList.java

@@ -0,0 +1,133 @@
+package lol.pyr.znpcsplus.util.list;
+
+import java.util.*;
+
+public class ImmutableArrayList<T> implements List<T> {
+    private final T[] elements;
+
+    public ImmutableArrayList(T[] array) {
+        this.elements = array;
+    }
+
+    @Override
+    public int size() {
+        return elements.length;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return elements.length != 0;
+    }
+
+    @Override
+    public boolean contains(Object o) {
+        return indexOf(o) != -1;
+    }
+
+    @Override
+    public Iterator<T> iterator() {
+        return new ArrayIterator<>(elements);
+    }
+
+    @Override
+    public Object[] toArray() {
+        return elements;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T1> T1[] toArray(T1[] a) {
+        return (T1[]) elements;
+    }
+
+    @Override
+    public boolean containsAll(Collection<?> c) {
+        for (Object obj : c) if (!contains(obj)) return false;
+        return true;
+    }
+
+    @Override
+    public List<T> subList(int fromIndex, int toIndex) {
+        return new ImmutableArrayList<>(Arrays.copyOfRange(elements, fromIndex, toIndex));
+    }
+
+    @Override
+    public T get(int index) {
+        return elements[index];
+    }
+
+    @Override
+    public int indexOf(Object o) {
+        for (int i = 0; i < elements.length; i++) if (Objects.equals(elements[i], o)) return i;
+        return -1;
+    }
+
+    @Override
+    public int lastIndexOf(Object o) {
+        for (int i = 0; i < elements.length; i++) {
+            int index = elements.length - (i + 1);
+            if (Objects.equals(elements[index], o)) return index;
+        }
+        return -1;
+    }
+
+    @Override
+    public ListIterator<T> listIterator() {
+        return new ArrayIterator<>(elements);
+    }
+
+    @Override
+    public ListIterator<T> listIterator(int index) {
+        return new ArrayIterator<>(elements);
+    }
+
+    @Override
+    public boolean add(T t) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean remove(Object o) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends T> c) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean addAll(int index, Collection<? extends T> c) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean removeAll(Collection<?> c) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean retainAll(Collection<?> c) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void clear() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public T set(int index, T element) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void add(int index, T element) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public T remove(int index) {
+        throw new UnsupportedOperationException();
+    }
+}

spigot/src/main/java/lol/pyr/znpcsplus/util/list/ListUtil.java

@@ -0,0 +1,10 @@
+package lol.pyr.znpcsplus.util.list;
+
+import java.util.*;
+
+public class ListUtil {
+    @SafeVarargs
+    public static <T> List<T> immutableList(T... elements) {
+        return new ImmutableArrayList<>(elements);
+    }
+}