--- a/net/minecraft/server/MinecraftServer.java
+++ b/net/minecraft/server/MinecraftServer.java
@@ -84,17 +84,6 @@
 import net.minecraft.obfuscate.DontObfuscate;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
-import net.minecraft.server.bossevents.CustomBossEvents;
-import net.minecraft.server.level.DemoMode;
-import net.minecraft.server.level.PlayerRespawnLogic;
-import net.minecraft.server.level.ServerChunkCache;
-import net.minecraft.server.level.ServerLevel;
-import net.minecraft.server.level.ServerPlayer;
-import net.minecraft.server.level.ServerPlayerGameMode;
-import net.minecraft.server.level.progress.ChunkProgressListener;
-import net.minecraft.server.level.progress.ChunkProgressListenerFactory;
-import net.minecraft.server.network.ServerConnectionListener;
-import net.minecraft.server.network.TextFilter;
 import net.minecraft.server.packs.PackType;
 import net.minecraft.server.packs.repository.Pack;
 import net.minecraft.server.packs.repository.PackRepository;
@@ -116,6 +105,7 @@
 import net.minecraft.util.RandomSource;
 import net.minecraft.util.SignatureValidator;
 import net.minecraft.util.TimeUtil;
+import net.minecraft.util.datafix.DataFixers;
 import net.minecraft.util.debugchart.RemoteDebugSampleType;
 import net.minecraft.util.debugchart.SampleLogger;
 import net.minecraft.util.debugchart.TpsDebugDimensions;
@@ -156,37 +146,73 @@
 import net.minecraft.world.level.biome.BiomeManager;
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.entity.FuelValues;
-import net.minecraft.world.level.border.BorderChangeListener;
 import net.minecraft.world.level.border.WorldBorder;
 import net.minecraft.world.level.chunk.storage.ChunkIOErrorReporter;
 import net.minecraft.world.level.chunk.storage.RegionStorageInfo;
 import net.minecraft.world.level.dimension.LevelStem;
-import net.minecraft.world.level.levelgen.Heightmap;
-import net.minecraft.world.level.levelgen.PatrolSpawner;
-import net.minecraft.world.level.levelgen.PhantomSpawner;
 import net.minecraft.world.level.levelgen.WorldOptions;
 import net.minecraft.world.level.levelgen.feature.ConfiguredFeature;
 import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplateManager;
+import net.minecraft.world.level.storage.WorldData;
+import org.slf4j.Logger;
+
+// CraftBukkit start
+import com.mojang.serialization.Dynamic;
+import com.mojang.serialization.Lifecycle;
+import java.io.File;
+import java.util.Random;
+import jline.console.ConsoleReader;
+import joptsimple.OptionSet;
+import net.minecraft.nbt.NbtException;
+import net.minecraft.nbt.ReportedNbtException;
+import net.minecraft.server.bossevents.CustomBossEvents;
+import net.minecraft.server.dedicated.DedicatedServer;
+import net.minecraft.server.dedicated.DedicatedServerProperties;
+import net.minecraft.server.level.DemoMode;
+import net.minecraft.server.level.PlayerRespawnLogic;
+import net.minecraft.server.level.ServerChunkCache;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.server.level.ServerPlayerGameMode;
+import net.minecraft.server.level.progress.ChunkProgressListener;
+import net.minecraft.server.level.progress.ChunkProgressListenerFactory;
+import net.minecraft.server.network.ServerConnectionListener;
+import net.minecraft.server.network.TextFilter;
+import net.minecraft.world.level.levelgen.Heightmap;
+import net.minecraft.world.level.levelgen.PatrolSpawner;
+import net.minecraft.world.level.levelgen.PhantomSpawner;
+import net.minecraft.world.level.levelgen.WorldDimensions;
+import net.minecraft.world.level.levelgen.presets.WorldPresets;
 import net.minecraft.world.level.storage.CommandStorage;
-import net.minecraft.world.level.storage.DerivedLevelData;
 import net.minecraft.world.level.storage.DimensionDataStorage;
 import net.minecraft.world.level.storage.LevelData;
+import net.minecraft.world.level.storage.LevelDataAndDimensions;
 import net.minecraft.world.level.storage.LevelResource;
 import net.minecraft.world.level.storage.LevelStorageSource;
+import net.minecraft.world.level.storage.LevelSummary;
 import net.minecraft.world.level.storage.PlayerDataStorage;
+import net.minecraft.world.level.storage.PrimaryLevelData;
 import net.minecraft.world.level.storage.ServerLevelData;
-import net.minecraft.world.level.storage.WorldData;
+import net.minecraft.world.level.validation.ContentValidationException;
 import net.minecraft.world.phys.Vec2;
 import net.minecraft.world.phys.Vec3;
-import org.slf4j.Logger;
+import org.bukkit.Bukkit;
+import org.bukkit.craftbukkit.CraftRegistry;
+import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.craftbukkit.Main;
+import org.bukkit.event.server.ServerLoadEvent;
+// CraftBukkit end
 
+import org.bukkit.craftbukkit.SpigotTimings; // Spigot
+
 public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTask> implements ServerInfo, ChunkIOErrorReporter, CommandSource {
 
     public static final Logger LOGGER = LogUtils.getLogger();
+    public static final net.kyori.adventure.text.logger.slf4j.ComponentLogger COMPONENT_LOGGER = net.kyori.adventure.text.logger.slf4j.ComponentLogger.logger(LOGGER.getName()); // Paper
     public static final String VANILLA_BRAND = "vanilla";
     private static final float AVERAGE_TICK_TIME_SMOOTHING = 0.8F;
     private static final int TICK_STATS_SPAN = 100;
-    private static final long OVERLOADED_THRESHOLD_NANOS = 20L * TimeUtil.NANOSECONDS_PER_SECOND / 20L;
+    private static final long OVERLOADED_THRESHOLD_NANOS = 30L * TimeUtil.NANOSECONDS_PER_SECOND / 20L; // CraftBukkit
     private static final int OVERLOADED_TICKS_THRESHOLD = 20;
     private static final long OVERLOADED_WARNING_INTERVAL_NANOS = 10L * TimeUtil.NANOSECONDS_PER_SECOND;
     private static final int OVERLOADED_TICKS_WARNING_INTERVAL = 100;
@@ -232,8 +258,7 @@
     private boolean preventProxyConnections;
     private boolean pvp;
     private boolean allowFlight;
-    @Nullable
-    private String motd;
+    private net.kyori.adventure.text.Component motd; // Paper - Adventure
     private int playerIdleTimeout;
     private final long[] tickTimesNanos;
     private long aggregatedTickTimesNanos;
@@ -276,6 +301,26 @@
     private static final AtomicReference<RuntimeException> fatalException = new AtomicReference();
     private final SuppressedExceptionCollector suppressedExceptions;
     private final DiscontinuousFrame tickFrame;
+
+    // CraftBukkit start
+    public final WorldLoader.DataLoadContext worldLoader;
+    public org.bukkit.craftbukkit.CraftServer server;
+    public OptionSet options;
+    public org.bukkit.command.ConsoleCommandSender console;
+    public ConsoleReader reader;
+    public static int currentTick = (int) (System.currentTimeMillis() / 50);
+    public java.util.Queue<Runnable> processQueue = new java.util.concurrent.ConcurrentLinkedQueue<Runnable>();
+    public int autosavePeriod;
+    public Commands vanillaCommandDispatcher;
+    private boolean forceTicks;
+    // CraftBukkit end
+    // Spigot start
+    public static final int TPS = 20;
+    public static final int TICK_TIME = 1000000000 / MinecraftServer.TPS;
+    private static final int SAMPLE_INTERVAL = 100;
+    public final double[] recentTps = new double[ 3 ];
+    // Spigot end
+    public final io.papermc.paper.configuration.PaperConfigurations paperConfigurations; // Paper - add paper configuration files
 
     public static <S extends MinecraftServer> S spin(Function<Thread, S> serverFactory) {
         AtomicReference<S> atomicreference = new AtomicReference();
@@ -290,14 +335,14 @@
             thread.setPriority(8);
         }
 
-        S s0 = (MinecraftServer) serverFactory.apply(thread);
+        S s0 = serverFactory.apply(thread); // CraftBukkit - decompile error
 
         atomicreference.set(s0);
         thread.start();
         return s0;
     }
 
-    public MinecraftServer(Thread serverThread, LevelStorageSource.LevelStorageAccess session, PackRepository dataPackManager, WorldStem saveLoader, Proxy proxy, DataFixer dataFixer, Services apiServices, ChunkProgressListenerFactory worldGenerationProgressListenerFactory) {
+    public MinecraftServer(OptionSet options, WorldLoader.DataLoadContext worldLoader, Thread thread, LevelStorageSource.LevelStorageAccess convertable_conversionsession, PackRepository resourcepackrepository, WorldStem worldstem, Proxy proxy, DataFixer datafixer, Services services, ChunkProgressListenerFactory worldloadlistenerfactory) {
         super("Server");
         this.metricsRecorder = InactiveMetricsRecorder.INSTANCE;
         this.onMetricsRecordingStopped = (methodprofilerresults) -> {
@@ -319,36 +364,64 @@
         this.scoreboard = new ServerScoreboard(this);
         this.customBossEvents = new CustomBossEvents();
         this.suppressedExceptions = new SuppressedExceptionCollector();
-        this.registries = saveLoader.registries();
-        this.worldData = saveLoader.worldData();
-        if (!this.registries.compositeAccess().lookupOrThrow(Registries.LEVEL_STEM).containsKey(LevelStem.OVERWORLD)) {
+        this.registries = worldstem.registries();
+        this.worldData = worldstem.worldData();
+        if (false && !this.registries.compositeAccess().lookupOrThrow(Registries.LEVEL_STEM).containsKey(LevelStem.OVERWORLD)) { // CraftBukkit - initialised later
             throw new IllegalStateException("Missing Overworld dimension data");
         } else {
             this.proxy = proxy;
-            this.packRepository = dataPackManager;
-            this.resources = new MinecraftServer.ReloadableResources(saveLoader.resourceManager(), saveLoader.dataPackResources());
-            this.services = apiServices;
-            if (apiServices.profileCache() != null) {
-                apiServices.profileCache().setExecutor(this);
+            this.packRepository = resourcepackrepository;
+            this.resources = new MinecraftServer.ReloadableResources(worldstem.resourceManager(), worldstem.dataPackResources());
+            this.services = services;
+            if (services.profileCache() != null) {
+                services.profileCache().setExecutor(this);
             }
 
-            this.connection = new ServerConnectionListener(this);
+            // this.connection = new ServerConnection(this); // Spigot
             this.tickRateManager = new ServerTickRateManager(this);
-            this.progressListenerFactory = worldGenerationProgressListenerFactory;
-            this.storageSource = session;
-            this.playerDataStorage = session.createPlayerStorage();
-            this.fixerUpper = dataFixer;
+            this.progressListenerFactory = worldloadlistenerfactory;
+            this.storageSource = convertable_conversionsession;
+            this.playerDataStorage = convertable_conversionsession.createPlayerStorage();
+            this.fixerUpper = datafixer;
             this.functionManager = new ServerFunctionManager(this, this.resources.managers.getFunctionLibrary());
             HolderGetter<Block> holdergetter = this.registries.compositeAccess().lookupOrThrow(Registries.BLOCK).filterFeatures(this.worldData.enabledFeatures());
 
-            this.structureTemplateManager = new StructureTemplateManager(saveLoader.resourceManager(), session, dataFixer, holdergetter);
-            this.serverThread = serverThread;
+            this.structureTemplateManager = new StructureTemplateManager(worldstem.resourceManager(), convertable_conversionsession, datafixer, holdergetter);
+            this.serverThread = thread;
             this.executor = Util.backgroundExecutor();
             this.potionBrewing = PotionBrewing.bootstrap(this.worldData.enabledFeatures());
             this.resources.managers.getRecipeManager().finalizeRecipeLoading(this.worldData.enabledFeatures());
             this.fuelValues = FuelValues.vanillaBurnTimes(this.registries.compositeAccess(), this.worldData.enabledFeatures());
             this.tickFrame = TracyClient.createDiscontinuousFrame("Server Tick");
         }
+        // CraftBukkit start
+        this.options = options;
+        this.worldLoader = worldLoader;
+        this.vanillaCommandDispatcher = worldstem.dataPackResources().commands; // CraftBukkit
+        // Try to see if we're actually running in a terminal, disable jline if not
+        if (System.console() == null && System.getProperty("jline.terminal") == null) {
+            System.setProperty("jline.terminal", "jline.UnsupportedTerminal");
+            Main.useJline = false;
+        }
+
+        try {
+            this.reader = new ConsoleReader(System.in, System.out);
+            this.reader.setExpandEvents(false); // Avoid parsing exceptions for uncommonly used event designators
+        } catch (Throwable e) {
+            try {
+                // Try again with jline disabled for Windows users without C++ 2008 Redistributable
+                System.setProperty("jline.terminal", "jline.UnsupportedTerminal");
+                System.setProperty("user.language", "en");
+                Main.useJline = false;
+                this.reader = new ConsoleReader(System.in, System.out);
+                this.reader.setExpandEvents(false);
+            } catch (IOException ex) {
+                MinecraftServer.LOGGER.warn((String) null, ex);
+            }
+        }
+        Runtime.getRuntime().addShutdownHook(new org.bukkit.craftbukkit.util.ServerShutdownThread(this));
+        // CraftBukkit end
+        this.paperConfigurations = services.paperConfigurations(); // Paper - add paper configuration files
     }
 
     private void readScoreboard(DimensionDataStorage persistentStateManager) {
@@ -357,7 +430,7 @@
 
     protected abstract boolean initServer() throws IOException;
 
-    protected void loadLevel() {
+    protected void loadLevel(String s) { // CraftBukkit
         if (!JvmProfiler.INSTANCE.isRunning()) {
             ;
         }
@@ -365,12 +438,8 @@
         boolean flag = false;
         ProfiledDuration profiledduration = JvmProfiler.INSTANCE.onWorldLoadedStarted();
 
-        this.worldData.setModdedInfo(this.getServerModName(), this.getModdedStatus().shouldReportAsModified());
-        ChunkProgressListener worldloadlistener = this.progressListenerFactory.create(this.worldData.getGameRules().getInt(GameRules.RULE_SPAWN_CHUNK_RADIUS));
+        this.loadWorld0(s); // CraftBukkit
 
-        this.createLevels(worldloadlistener);
-        this.forceDifficulty();
-        this.prepareLevels(worldloadlistener);
         if (profiledduration != null) {
             profiledduration.finish(true);
         }
@@ -387,23 +456,217 @@
 
     protected void forceDifficulty() {}
 
-    protected void createLevels(ChunkProgressListener worldGenerationProgressListener) {
-        ServerLevelData iworlddataserver = this.worldData.overworldData();
-        boolean flag = this.worldData.isDebugWorld();
-        Registry<LevelStem> iregistry = this.registries.compositeAccess().lookupOrThrow(Registries.LEVEL_STEM);
-        WorldOptions worldoptions = this.worldData.worldGenOptions();
-        long i = worldoptions.seed();
-        long j = BiomeManager.obfuscateSeed(i);
-        List<CustomSpawner> list = ImmutableList.of(new PhantomSpawner(), new PatrolSpawner(), new CatSpawner(), new VillageSiege(), new WanderingTraderSpawner(iworlddataserver));
-        LevelStem worlddimension = (LevelStem) iregistry.getValue(LevelStem.OVERWORLD);
-        ServerLevel worldserver = new ServerLevel(this, this.executor, this.storageSource, iworlddataserver, Level.OVERWORLD, worlddimension, worldGenerationProgressListener, flag, j, list, true, (RandomSequences) null);
+    // CraftBukkit start
+    private void loadWorld0(String s) {
+        LevelStorageSource.LevelStorageAccess worldSession = this.storageSource;
 
-        this.levels.put(Level.OVERWORLD, worldserver);
-        DimensionDataStorage worldpersistentdata = worldserver.getDataStorage();
+        RegistryAccess.Frozen iregistrycustom_dimension = this.registries.compositeAccess();
+        Registry<LevelStem> dimensions = iregistrycustom_dimension.lookupOrThrow(Registries.LEVEL_STEM);
+        for (LevelStem worldDimension : dimensions) {
+            ResourceKey<LevelStem> dimensionKey = dimensions.getResourceKey(worldDimension).get();
 
-        this.readScoreboard(worldpersistentdata);
-        this.commandStorage = new CommandStorage(worldpersistentdata);
+            ServerLevel world;
+            int dimension = 0;
+
+            if (dimensionKey == LevelStem.NETHER) {
+                if (this.server.getAllowNether()) {
+                    dimension = -1;
+                } else {
+                    continue;
+                }
+            } else if (dimensionKey == LevelStem.END) {
+                if (this.server.getAllowEnd()) {
+                    dimension = 1;
+                } else {
+                    continue;
+                }
+            } else if (dimensionKey != LevelStem.OVERWORLD) {
+                dimension = -999;
+            }
+
+            String worldType = (dimension == -999) ? dimensionKey.location().getNamespace() + "_" + dimensionKey.location().getPath() : org.bukkit.World.Environment.getEnvironment(dimension).toString().toLowerCase(Locale.ROOT);
+            String name = (dimensionKey == LevelStem.OVERWORLD) ? s : s + "_" + worldType;
+            if (dimension != 0) {
+                File newWorld = LevelStorageSource.getStorageFolder(new File(name).toPath(), dimensionKey).toFile();
+                File oldWorld = LevelStorageSource.getStorageFolder(new File(s).toPath(), dimensionKey).toFile();
+                File oldLevelDat = new File(new File(s), "level.dat"); // The data folders exist on first run as they are created in the PersistentCollection constructor above, but the level.dat won't
+
+                if (!newWorld.isDirectory() && oldWorld.isDirectory() && oldLevelDat.isFile()) {
+                    MinecraftServer.LOGGER.info("---- Migration of old " + worldType + " folder required ----");
+                    MinecraftServer.LOGGER.info("Unfortunately due to the way that Minecraft implemented multiworld support in 1.6, Bukkit requires that you move your " + worldType + " folder to a new location in order to operate correctly.");
+                    MinecraftServer.LOGGER.info("We will move this folder for you, but it will mean that you need to move it back should you wish to stop using Bukkit in the future.");
+                    MinecraftServer.LOGGER.info("Attempting to move " + oldWorld + " to " + newWorld + "...");
+
+                    if (newWorld.exists()) {
+                        MinecraftServer.LOGGER.warn("A file or folder already exists at " + newWorld + "!");
+                        MinecraftServer.LOGGER.info("---- Migration of old " + worldType + " folder failed ----");
+                    } else if (newWorld.getParentFile().mkdirs()) {
+                        if (oldWorld.renameTo(newWorld)) {
+                            MinecraftServer.LOGGER.info("Success! To restore " + worldType + " in the future, simply move " + newWorld + " to " + oldWorld);
+                            // Migrate world data too.
+                            try {
+                                com.google.common.io.Files.copy(oldLevelDat, new File(new File(name), "level.dat"));
+                                org.apache.commons.io.FileUtils.copyDirectory(new File(new File(s), "data"), new File(new File(name), "data"));
+                            } catch (IOException exception) {
+                                MinecraftServer.LOGGER.warn("Unable to migrate world data.");
+                            }
+                            MinecraftServer.LOGGER.info("---- Migration of old " + worldType + " folder complete ----");
+                        } else {
+                            MinecraftServer.LOGGER.warn("Could not move folder " + oldWorld + " to " + newWorld + "!");
+                            MinecraftServer.LOGGER.info("---- Migration of old " + worldType + " folder failed ----");
+                        }
+                    } else {
+                        MinecraftServer.LOGGER.warn("Could not create path for " + newWorld + "!");
+                        MinecraftServer.LOGGER.info("---- Migration of old " + worldType + " folder failed ----");
+                    }
+                }
+
+                try {
+                    worldSession = LevelStorageSource.createDefault(this.server.getWorldContainer().toPath()).validateAndCreateAccess(name, dimensionKey);
+                } catch (IOException | ContentValidationException ex) {
+                    throw new RuntimeException(ex);
+                }
+            }
+
+            Dynamic<?> dynamic;
+            if (worldSession.hasWorldData()) {
+                LevelSummary worldinfo;
+
+                try {
+                    dynamic = worldSession.getDataTag();
+                    worldinfo = worldSession.getSummary(dynamic);
+                } catch (NbtException | ReportedNbtException | IOException ioexception) {
+                    LevelStorageSource.LevelDirectory convertable_b = worldSession.getLevelDirectory();
+
+                    MinecraftServer.LOGGER.warn("Failed to load world data from {}", convertable_b.dataFile(), ioexception);
+                    MinecraftServer.LOGGER.info("Attempting to use fallback");
+
+                    try {
+                        dynamic = worldSession.getDataTagFallback();
+                        worldinfo = worldSession.getSummary(dynamic);
+                    } catch (NbtException | ReportedNbtException | IOException ioexception1) {
+                        MinecraftServer.LOGGER.error("Failed to load world data from {}", convertable_b.oldDataFile(), ioexception1);
+                        MinecraftServer.LOGGER.error("Failed to load world data from {} and {}. World files may be corrupted. Shutting down.", convertable_b.dataFile(), convertable_b.oldDataFile());
+                        return;
+                    }
+
+                    worldSession.restoreLevelDataFromOld();
+                }
+
+                if (worldinfo.requiresManualConversion()) {
+                    MinecraftServer.LOGGER.info("This world must be opened in an older version (like 1.6.4) to be safely converted");
+                    return;
+                }
+
+                if (!worldinfo.isCompatible()) {
+                    MinecraftServer.LOGGER.info("This world was created by an incompatible version.");
+                    return;
+                }
+            } else {
+                dynamic = null;
+            }
+
+            org.bukkit.generator.ChunkGenerator gen = this.server.getGenerator(name);
+            org.bukkit.generator.BiomeProvider biomeProvider = this.server.getBiomeProvider(name);
+
+            PrimaryLevelData worlddata;
+            WorldLoader.DataLoadContext worldloader_a = this.worldLoader;
+            Registry<LevelStem> iregistry = worldloader_a.datapackDimensions().lookupOrThrow(Registries.LEVEL_STEM);
+            if (dynamic != null) {
+                LevelDataAndDimensions leveldataanddimensions = LevelStorageSource.getLevelDataAndDimensions(dynamic, worldloader_a.dataConfiguration(), iregistry, worldloader_a.datapackWorldgen());
+
+                worlddata = (PrimaryLevelData) leveldataanddimensions.worldData();
+            } else {
+                LevelSettings worldsettings;
+                WorldOptions worldoptions;
+                WorldDimensions worlddimensions;
+
+                if (this.isDemo()) {
+                    worldsettings = MinecraftServer.DEMO_SETTINGS;
+                    worldoptions = WorldOptions.DEMO_OPTIONS;
+                    worlddimensions = WorldPresets.createNormalWorldDimensions(worldloader_a.datapackWorldgen());
+                } else {
+                    DedicatedServerProperties dedicatedserverproperties = ((DedicatedServer) this).getProperties();
+
+                    worldsettings = new LevelSettings(dedicatedserverproperties.levelName, dedicatedserverproperties.gamemode, dedicatedserverproperties.hardcore, dedicatedserverproperties.difficulty, false, new GameRules(worldloader_a.dataConfiguration().enabledFeatures()), worldloader_a.dataConfiguration());
+                    worldoptions = this.options.has("bonusChest") ? dedicatedserverproperties.worldOptions.withBonusChest(true) : dedicatedserverproperties.worldOptions;
+                    worlddimensions = dedicatedserverproperties.createDimensions(worldloader_a.datapackWorldgen());
+                }
+
+                WorldDimensions.Complete worlddimensions_b = worlddimensions.bake(iregistry);
+                Lifecycle lifecycle = worlddimensions_b.lifecycle().add(worldloader_a.datapackWorldgen().allRegistriesLifecycle());
+
+                worlddata = new PrimaryLevelData(worldsettings, worldoptions, worlddimensions_b.specialWorldProperty(), lifecycle);
+            }
+            worlddata.checkName(name); // CraftBukkit - Migration did not rewrite the level.dat; This forces 1.8 to take the last loaded world as respawn (in this case the end)
+            if (this.options.has("forceUpgrade")) {
+                net.minecraft.server.Main.forceUpgrade(worldSession, DataFixers.getDataFixer(), this.options.has("eraseCache"), () -> {
+                    return true;
+                }, iregistrycustom_dimension, this.options.has("recreateRegionFiles"));
+            }
+
+            PrimaryLevelData iworlddataserver = worlddata;
+            boolean flag = worlddata.isDebugWorld();
+            WorldOptions worldoptions = worlddata.worldGenOptions();
+            long i = worldoptions.seed();
+            long j = BiomeManager.obfuscateSeed(i);
+            List<CustomSpawner> list = ImmutableList.of(new PhantomSpawner(), new PatrolSpawner(), new CatSpawner(), new VillageSiege(), new WanderingTraderSpawner(iworlddataserver));
+            LevelStem worlddimension = (LevelStem) dimensions.getValue(dimensionKey);
+
+            org.bukkit.generator.WorldInfo worldInfo = new org.bukkit.craftbukkit.generator.CraftWorldInfo(iworlddataserver, worldSession, org.bukkit.World.Environment.getEnvironment(dimension), worlddimension.type().value());
+            if (biomeProvider == null && gen != null) {
+                biomeProvider = gen.getDefaultBiomeProvider(worldInfo);
+            }
+
+            ResourceKey<Level> worldKey = ResourceKey.create(Registries.DIMENSION, dimensionKey.location());
+
+            if (dimensionKey == LevelStem.OVERWORLD) {
+                this.worldData = worlddata;
+                this.worldData.setGameType(((DedicatedServer) this).getProperties().gamemode); // From DedicatedServer.init
+
+                ChunkProgressListener worldloadlistener = this.progressListenerFactory.create(this.worldData.getGameRules().getInt(GameRules.RULE_SPAWN_CHUNK_RADIUS));
+
+                world = new ServerLevel(this, this.executor, worldSession, iworlddataserver, worldKey, worlddimension, worldloadlistener, flag, j, list, true, (RandomSequences) null, org.bukkit.World.Environment.getEnvironment(dimension), gen, biomeProvider);
+                DimensionDataStorage worldpersistentdata = world.getDataStorage();
+                this.readScoreboard(worldpersistentdata);
+                this.server.scoreboardManager = new org.bukkit.craftbukkit.scoreboard.CraftScoreboardManager(this, world.getScoreboard());
+                this.commandStorage = new CommandStorage(worldpersistentdata);
+            } else {
+                ChunkProgressListener worldloadlistener = this.progressListenerFactory.create(this.worldData.getGameRules().getInt(GameRules.RULE_SPAWN_CHUNK_RADIUS));
+                world = new ServerLevel(this, this.executor, worldSession, iworlddataserver, worldKey, worlddimension, worldloadlistener, flag, j, ImmutableList.of(), true, this.overworld().getRandomSequences(), org.bukkit.World.Environment.getEnvironment(dimension), gen, biomeProvider);
+            }
+
+            worlddata.setModdedInfo(this.getServerModName(), this.getModdedStatus().shouldReportAsModified());
+            this.initWorld(world, worlddata, this.worldData, worldoptions);
+
+            this.addLevel(world);
+            this.getPlayerList().addWorldborderListener(world);
+
+            if (worlddata.getCustomBossEvents() != null) {
+                this.getCustomBossEvents().load(worlddata.getCustomBossEvents(), this.registryAccess());
+            }
+        }
+        this.forceDifficulty();
+        for (ServerLevel worldserver : this.getAllLevels()) {
+            this.prepareLevels(worldserver.getChunkSource().chunkMap.progressListener, worldserver);
+            worldserver.entityManager.tick(); // SPIGOT-6526: Load pending entities so they are available to the API
+            this.server.getPluginManager().callEvent(new org.bukkit.event.world.WorldLoadEvent(worldserver.getWorld()));
+        }
+
+        this.server.enablePlugins(org.bukkit.plugin.PluginLoadOrder.POSTWORLD);
+        this.server.getPluginManager().callEvent(new ServerLoadEvent(ServerLoadEvent.LoadType.STARTUP));
+        this.connection.acceptConnections();
+    }
+
+    public void initWorld(ServerLevel worldserver, ServerLevelData iworlddataserver, WorldData saveData, WorldOptions worldoptions) {
+        boolean flag = saveData.isDebugWorld();
+        // CraftBukkit start
+        if (worldserver.generator != null) {
+            worldserver.getWorld().getPopulators().addAll(worldserver.generator.getDefaultPopulators(worldserver.getWorld()));
+        }
         WorldBorder worldborder = worldserver.getWorldBorder();
+        worldborder.applySettings(iworlddataserver.getWorldBorder()); // CraftBukkit - move up so that WorldBorder is set during WorldInitEvent
+        this.server.getPluginManager().callEvent(new org.bukkit.event.world.WorldInitEvent(worldserver.getWorld())); // CraftBukkit - SPIGOT-5569: Call WorldInitEvent before any chunks are generated
 
         if (!iworlddataserver.isInitialized()) {
             try {
@@ -427,30 +690,8 @@
             iworlddataserver.setInitialized(true);
         }
 
-        this.getPlayerList().addWorldborderListener(worldserver);
-        if (this.worldData.getCustomBossEvents() != null) {
-            this.getCustomBossEvents().load(this.worldData.getCustomBossEvents(), this.registryAccess());
-        }
-
-        RandomSequences randomsequences = worldserver.getRandomSequences();
-        Iterator iterator = iregistry.entrySet().iterator();
-
-        while (iterator.hasNext()) {
-            Entry<ResourceKey<LevelStem>, LevelStem> entry = (Entry) iterator.next();
-            ResourceKey<LevelStem> resourcekey = (ResourceKey) entry.getKey();
-
-            if (resourcekey != LevelStem.OVERWORLD) {
-                ResourceKey<Level> resourcekey1 = ResourceKey.create(Registries.DIMENSION, resourcekey.location());
-                DerivedLevelData secondaryworlddata = new DerivedLevelData(this.worldData, iworlddataserver);
-                ServerLevel worldserver1 = new ServerLevel(this, this.executor, this.storageSource, secondaryworlddata, resourcekey1, (LevelStem) entry.getValue(), worldGenerationProgressListener, flag, j, ImmutableList.of(), false, randomsequences);
-
-                worldborder.addListener(new BorderChangeListener.DelegateBorderChangeListener(worldserver1.getWorldBorder()));
-                this.levels.put(resourcekey1, worldserver1);
-            }
-        }
-
-        worldborder.applySettings(iworlddataserver.getWorldBorder());
     }
+    // CraftBukkit end
 
     private static void setInitialSpawn(ServerLevel world, ServerLevelData worldProperties, boolean bonusChest, boolean debugWorld) {
         if (debugWorld) {
@@ -458,6 +699,21 @@
         } else {
             ServerChunkCache chunkproviderserver = world.getChunkSource();
             ChunkPos chunkcoordintpair = new ChunkPos(chunkproviderserver.randomState().sampler().findSpawnPosition());
+            // CraftBukkit start
+            if (world.generator != null) {
+                Random rand = new Random(world.getSeed());
+                org.bukkit.Location spawn = world.generator.getFixedSpawnLocation(world.getWorld(), rand);
+
+                if (spawn != null) {
+                    if (spawn.getWorld() != world.getWorld()) {
+                        throw new IllegalStateException("Cannot set spawn point for " + worldProperties.getLevelName() + " to be in another world (" + spawn.getWorld().getName() + ")");
+                    } else {
+                        worldProperties.setSpawn(new BlockPos(spawn.getBlockX(), spawn.getBlockY(), spawn.getBlockZ()), spawn.getYaw());
+                        return;
+                    }
+                }
+            }
+            // CraftBukkit end
             int i = chunkproviderserver.getGenerator().getSpawnHeight(world);
 
             if (i < world.getMinY()) {
@@ -516,31 +772,36 @@
         iworlddataserver.setGameType(GameType.SPECTATOR);
     }
 
-    public void prepareLevels(ChunkProgressListener worldGenerationProgressListener) {
-        ServerLevel worldserver = this.overworld();
+    // CraftBukkit start
+    public void prepareLevels(ChunkProgressListener worldloadlistener, ServerLevel worldserver) {
+        // WorldServer worldserver = this.overworld();
+        this.forceTicks = true;
+        // CraftBukkit end
 
         MinecraftServer.LOGGER.info("Preparing start region for dimension {}", worldserver.dimension().location());
         BlockPos blockposition = worldserver.getSharedSpawnPos();
 
-        worldGenerationProgressListener.updateSpawnPos(new ChunkPos(blockposition));
+        worldloadlistener.updateSpawnPos(new ChunkPos(blockposition));
         ServerChunkCache chunkproviderserver = worldserver.getChunkSource();
 
         this.nextTickTimeNanos = Util.getNanos();
         worldserver.setDefaultSpawnPos(blockposition, worldserver.getSharedSpawnAngle());
-        int i = this.getGameRules().getInt(GameRules.RULE_SPAWN_CHUNK_RADIUS);
+        int i = worldserver.getGameRules().getInt(GameRules.RULE_SPAWN_CHUNK_RADIUS); // CraftBukkit - per-world
         int j = i > 0 ? Mth.square(ChunkProgressListener.calculateDiameter(i)) : 0;
 
         while (chunkproviderserver.getTickingGenerated() < j) {
-            this.nextTickTimeNanos = Util.getNanos() + MinecraftServer.PREPARE_LEVELS_DEFAULT_DELAY_NANOS;
-            this.waitUntilNextTick();
+            // CraftBukkit start
+            // this.nextTickTimeNanos = SystemUtils.getNanos() + MinecraftServer.PREPARE_LEVELS_DEFAULT_DELAY_NANOS;
+            this.executeModerately();
         }
 
-        this.nextTickTimeNanos = Util.getNanos() + MinecraftServer.PREPARE_LEVELS_DEFAULT_DELAY_NANOS;
-        this.waitUntilNextTick();
-        Iterator iterator = this.levels.values().iterator();
+        // this.nextTickTimeNanos = SystemUtils.getNanos() + MinecraftServer.PREPARE_LEVELS_DEFAULT_DELAY_NANOS;
+        this.executeModerately();
+        // Iterator iterator = this.levels.values().iterator();
 
-        while (iterator.hasNext()) {
-            ServerLevel worldserver1 = (ServerLevel) iterator.next();
+        if (true) {
+            ServerLevel worldserver1 = worldserver;
+            // CraftBukkit end
             ForcedChunksSavedData forcedchunk = (ForcedChunksSavedData) worldserver1.getDataStorage().get(ForcedChunksSavedData.factory(), "chunks");
 
             if (forcedchunk != null) {
@@ -555,10 +816,17 @@
             }
         }
 
-        this.nextTickTimeNanos = Util.getNanos() + MinecraftServer.PREPARE_LEVELS_DEFAULT_DELAY_NANOS;
-        this.waitUntilNextTick();
-        worldGenerationProgressListener.stop();
-        this.updateMobSpawningFlags();
+        // CraftBukkit start
+        // this.nextTickTimeNanos = SystemUtils.getNanos() + MinecraftServer.PREPARE_LEVELS_DEFAULT_DELAY_NANOS;
+        this.executeModerately();
+        // CraftBukkit end
+        worldloadlistener.stop();
+        // CraftBukkit start
+        // this.updateMobSpawningFlags();
+        worldserver.setSpawnSettings(this.isSpawningMonsters());
+
+        this.forceTicks = false;
+        // CraftBukkit end
     }
 
     public GameType getDefaultGameType() {
@@ -588,12 +856,16 @@
             worldserver.save((ProgressListener) null, flush, worldserver.noSave && !force);
         }
 
-        ServerLevel worldserver1 = this.overworld();
-        ServerLevelData iworlddataserver = this.worldData.overworldData();
+        // CraftBukkit start - moved to WorldServer.save
+        /*
+        WorldServer worldserver1 = this.overworld();
+        IWorldDataServer iworlddataserver = this.worldData.overworldData();
 
         iworlddataserver.setWorldBorder(worldserver1.getWorldBorder().createSettings());
         this.worldData.setCustomBossEvents(this.getCustomBossEvents().save(this.registryAccess()));
         this.storageSource.saveDataTag(this.registryAccess(), this.worldData, this.getPlayerList().getSingleplayerData());
+        */
+        // CraftBukkit end
         if (flush) {
             Iterator iterator1 = this.getAllLevels().iterator();
 
@@ -628,18 +900,40 @@
         this.stopServer();
     }
 
+    // CraftBukkit start
+    private boolean hasStopped = false;
+    private final Object stopLock = new Object();
+    public final boolean hasStopped() {
+        synchronized (this.stopLock) {
+            return this.hasStopped;
+        }
+    }
+    // CraftBukkit end
+
     public void stopServer() {
+        // CraftBukkit start - prevent double stopping on multiple threads
+        synchronized(this.stopLock) {
+            if (this.hasStopped) return;
+            this.hasStopped = true;
+        }
+        // CraftBukkit end
         if (this.metricsRecorder.isRecording()) {
             this.cancelRecordingMetrics();
         }
 
         MinecraftServer.LOGGER.info("Stopping server");
+        // CraftBukkit start
+        if (this.server != null) {
+            this.server.disablePlugins();
+        }
+        // CraftBukkit end
         this.getConnection().stop();
         this.isSaving = true;
         if (this.playerList != null) {
             MinecraftServer.LOGGER.info("Saving players");
             this.playerList.saveAll();
             this.playerList.removeAll();
+            try { Thread.sleep(100); } catch (InterruptedException ex) {} // CraftBukkit - SPIGOT-625 - give server at least a chance to send packets
         }
 
         MinecraftServer.LOGGER.info("Saving worlds");
@@ -693,6 +987,15 @@
         } catch (IOException ioexception1) {
             MinecraftServer.LOGGER.error("Failed to unlock level {}", this.storageSource.getLevelId(), ioexception1);
         }
+        // Spigot start
+        io.papermc.paper.util.MCUtil.ASYNC_EXECUTOR.shutdown(); // Paper
+        try { io.papermc.paper.util.MCUtil.ASYNC_EXECUTOR.awaitTermination(30, java.util.concurrent.TimeUnit.SECONDS); // Paper
+        } catch (java.lang.InterruptedException ignored) {} // Paper
+        if (org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly) {
+            MinecraftServer.LOGGER.info("Saving usercache.json");
+            this.getProfileCache().save();
+        }
+        // Spigot end
 
     }
 
@@ -720,6 +1023,13 @@
 
     }
 
+    // Spigot Start
+    private static double calcTps(double avg, double exp, double tps)
+    {
+        return ( avg * exp ) + ( tps * ( 1 - exp ) );
+    }
+    // Spigot End
+
     protected void runServer() {
         try {
             if (!this.initServer()) {
@@ -727,9 +1037,12 @@
             }
 
             this.nextTickTimeNanos = Util.getNanos();
-            this.statusIcon = (ServerStatus.Favicon) this.loadStatusIcon().orElse((Object) null);
+            this.statusIcon = (ServerStatus.Favicon) this.loadStatusIcon().orElse(null); // CraftBukkit - decompile error
             this.status = this.buildServerStatus();
 
+            // Spigot start
+            Arrays.fill( this.recentTps, 20 );
+            long tickSection = Util.getMillis(), tickCount = 1;
             while (this.running) {
                 long i;
 
@@ -744,11 +1057,23 @@
                     if (j > MinecraftServer.OVERLOADED_THRESHOLD_NANOS + 20L * i && this.nextTickTimeNanos - this.lastOverloadWarningNanos >= MinecraftServer.OVERLOADED_WARNING_INTERVAL_NANOS + 100L * i) {
                         long k = j / i;
 
+                        if (this.server.getWarnOnOverload()) // CraftBukkit
                         MinecraftServer.LOGGER.warn("Can't keep up! Is the server overloaded? Running {}ms or {} ticks behind", j / TimeUtil.NANOSECONDS_PER_MILLISECOND, k);
                         this.nextTickTimeNanos += k * i;
                         this.lastOverloadWarningNanos = this.nextTickTimeNanos;
                     }
                 }
+                // Spigot start
+                if ( tickCount++ % MinecraftServer.SAMPLE_INTERVAL == 0 )
+                {
+                    long curTime = Util.getMillis();
+                    double currentTps = 1E3 / ( curTime - tickSection ) * MinecraftServer.SAMPLE_INTERVAL;
+                    this.recentTps[0] = MinecraftServer.calcTps( this.recentTps[0], 0.92, currentTps ); // 1/exp(5sec/1min)
+                    this.recentTps[1] = MinecraftServer.calcTps( this.recentTps[1], 0.9835, currentTps ); // 1/exp(5sec/5min)
+                    this.recentTps[2] = MinecraftServer.calcTps( this.recentTps[2], 0.9945, currentTps ); // 1/exp(5sec/15min)
+                    tickSection = curTime;
+                }
+                // Spigot end
 
                 boolean flag = i == 0L;
 
@@ -757,6 +1082,7 @@
                     this.debugCommandProfiler = new MinecraftServer.TimeProfiler(Util.getNanos(), this.tickCount);
                 }
 
+                MinecraftServer.currentTick = (int) (System.currentTimeMillis() / 50); // CraftBukkit
                 this.nextTickTimeNanos += i;
 
                 try {
@@ -830,6 +1156,13 @@
                     this.services.profileCache().clearExecutor();
                 }
 
+                org.spigotmc.WatchdogThread.doStop(); // Spigot
+                // CraftBukkit start - Restore terminal to original settings
+                try {
+                    this.reader.getTerminal().restore();
+                } catch (Exception ignored) {
+                }
+                // CraftBukkit end
                 this.onServerExit();
             }
 
@@ -889,9 +1222,16 @@
     }
 
     private boolean haveTime() {
-        return this.runningTask() || Util.getNanos() < (this.mayHaveDelayedTasks ? this.delayedTasksMaxNextTickTimeNanos : this.nextTickTimeNanos);
+        // CraftBukkit start
+        return this.forceTicks || this.runningTask() || Util.getNanos() < (this.mayHaveDelayedTasks ? this.delayedTasksMaxNextTickTimeNanos : this.nextTickTimeNanos);
     }
 
+    private void executeModerately() {
+        this.runAllTasks();
+        java.util.concurrent.locks.LockSupport.parkNanos("executing tasks", 1000L);
+        // CraftBukkit end
+    }
+
     public static boolean throwIfFatalException() {
         RuntimeException runtimeexception = (RuntimeException) MinecraftServer.fatalException.get();
 
@@ -903,7 +1243,7 @@
     }
 
     public static void setFatalException(RuntimeException exception) {
-        MinecraftServer.fatalException.compareAndSet((Object) null, exception);
+        MinecraftServer.fatalException.compareAndSet(null, exception); // CraftBukkit - decompile error
     }
 
     @Override
@@ -977,7 +1317,7 @@
         }
     }
 
-    public void doRunTask(TickTask ticktask) {
+    public void doRunTask(TickTask ticktask) { // CraftBukkit - decompile error
         Profiler.get().incrementCounter("runTask");
         super.doRunTask(ticktask);
     }
@@ -1025,6 +1365,7 @@
     }
 
     public void tickServer(BooleanSupplier shouldKeepTicking) {
+        org.spigotmc.WatchdogThread.tick(); // Spigot
         long i = Util.getNanos();
         int j = this.pauseWhileEmptySeconds() * 20;
 
@@ -1041,11 +1382,13 @@
                     this.autoSave();
                 }
 
+                this.server.getScheduler().mainThreadHeartbeat(); // CraftBukkit
                 this.tickConnection();
                 return;
             }
         }
 
+        SpigotTimings.serverTickTimer.startTiming(); // Spigot
         ++this.tickCount;
         this.tickRateManager.tick();
         this.tickChildren(shouldKeepTicking);
@@ -1055,7 +1398,7 @@
         }
 
         --this.ticksUntilAutosave;
-        if (this.ticksUntilAutosave <= 0) {
+        if (this.autosavePeriod > 0 && this.ticksUntilAutosave <= 0) { // CraftBukkit
             this.autoSave();
         }
 
@@ -1071,10 +1414,13 @@
         this.smoothedTickTimeMillis = this.smoothedTickTimeMillis * 0.8F + (float) k / (float) TimeUtil.NANOSECONDS_PER_MILLISECOND * 0.19999999F;
         this.logTickMethodTime(i);
         gameprofilerfiller.pop();
+        SpigotTimings.serverTickTimer.stopTiming(); // Spigot
+        org.spigotmc.CustomTimingsHandler.tick(); // Spigot
     }
 
     private void autoSave() {
-        this.ticksUntilAutosave = this.computeNextAutosaveInterval();
+        this.ticksUntilAutosave = this.autosavePeriod; // CraftBukkit
+        SpigotTimings.worldSaveTimer.startTiming(); // Spigot
         MinecraftServer.LOGGER.debug("Autosave started");
         ProfilerFiller gameprofilerfiller = Profiler.get();
 
@@ -1082,6 +1428,7 @@
         this.saveEverything(true, false, false);
         gameprofilerfiller.pop();
         MinecraftServer.LOGGER.debug("Autosave finished");
+        SpigotTimings.worldSaveTimer.stopTiming(); // Spigot
     }
 
     private void logTickMethodTime(long tickStartTime) {
@@ -1123,7 +1470,7 @@
     private ServerStatus buildServerStatus() {
         ServerStatus.Players serverping_serverpingplayersample = this.buildPlayerStatus();
 
-        return new ServerStatus(Component.nullToEmpty(this.motd), Optional.of(serverping_serverpingplayersample), Optional.of(ServerStatus.Version.current()), Optional.ofNullable(this.statusIcon), this.enforceSecureProfile());
+        return new ServerStatus(io.papermc.paper.adventure.PaperAdventure.asVanilla(this.motd), Optional.of(serverping_serverpingplayersample), Optional.of(ServerStatus.Version.current()), Optional.ofNullable(this.statusIcon), this.enforceSecureProfile()); // Paper - Adventure
     }
 
     private ServerStatus.Players buildPlayerStatus() {
@@ -1154,11 +1501,35 @@
         this.getPlayerList().getPlayers().forEach((entityplayer) -> {
             entityplayer.connection.suspendFlushing();
         });
+        SpigotTimings.schedulerTimer.startTiming(); // Spigot
+        this.server.getScheduler().mainThreadHeartbeat(); // CraftBukkit
+        SpigotTimings.schedulerTimer.stopTiming(); // Spigot
+        io.papermc.paper.adventure.providers.ClickCallbackProviderImpl.CALLBACK_MANAGER.handleQueue(this.tickCount); // Paper
         gameprofilerfiller.push("commandFunctions");
+        SpigotTimings.commandFunctionsTimer.startTiming(); // Spigot
         this.getFunctions().tick();
+        SpigotTimings.commandFunctionsTimer.stopTiming(); // Spigot
         gameprofilerfiller.popPush("levels");
         Iterator iterator = this.getAllLevels().iterator();
 
+        // CraftBukkit start
+        // Run tasks that are waiting on processing
+        SpigotTimings.processQueueTimer.startTiming(); // Spigot
+        while (!this.processQueue.isEmpty()) {
+            this.processQueue.remove().run();
+        }
+        SpigotTimings.processQueueTimer.stopTiming(); // Spigot
+
+        SpigotTimings.timeUpdateTimer.startTiming(); // Spigot
+        // Send time updates to everyone, it will get the right time from the world the player is in.
+        if (this.tickCount % 20 == 0) {
+            for (int i = 0; i < this.getPlayerList().players.size(); ++i) {
+                ServerPlayer entityplayer = (ServerPlayer) this.getPlayerList().players.get(i);
+                entityplayer.connection.send(new ClientboundSetTimePacket(entityplayer.level().getGameTime(), entityplayer.getPlayerTime(), entityplayer.serverLevel().getGameRules().getBoolean(GameRules.RULE_DAYLIGHT))); // Add support for per player time
+            }
+        }
+        SpigotTimings.timeUpdateTimer.stopTiming(); // Spigot
+
         while (iterator.hasNext()) {
             ServerLevel worldserver = (ServerLevel) iterator.next();
 
@@ -1167,16 +1538,20 @@
 
                 return s + " " + String.valueOf(worldserver.dimension().location());
             });
+            /* Drop global time updates
             if (this.tickCount % 20 == 0) {
                 gameprofilerfiller.push("timeSync");
                 this.synchronizeTime(worldserver);
                 gameprofilerfiller.pop();
             }
+            // CraftBukkit end */
 
             gameprofilerfiller.push("tick");
 
             try {
+                worldserver.timings.doTick.startTiming(); // Spigot
                 worldserver.tick(shouldKeepTicking);
+                worldserver.timings.doTick.stopTiming(); // Spigot
             } catch (Throwable throwable) {
                 CrashReport crashreport = CrashReport.forThrowable(throwable, "Exception ticking world");
 
@@ -1189,18 +1564,24 @@
         }
 
         gameprofilerfiller.popPush("connection");
+        SpigotTimings.connectionTimer.startTiming(); // Spigot
         this.tickConnection();
+        SpigotTimings.connectionTimer.stopTiming(); // Spigot
         gameprofilerfiller.popPush("players");
+        SpigotTimings.playerListTimer.startTiming(); // Spigot
         this.playerList.tick();
+        SpigotTimings.playerListTimer.stopTiming(); // Spigot
         if (SharedConstants.IS_RUNNING_IN_IDE && this.tickRateManager.runsNormally()) {
             GameTestTicker.SINGLETON.tick();
         }
 
         gameprofilerfiller.popPush("server gui refresh");
 
+        SpigotTimings.tickablesTimer.startTiming(); // Spigot
         for (int i = 0; i < this.tickables.size(); ++i) {
             ((Runnable) this.tickables.get(i)).run();
         }
+        SpigotTimings.tickablesTimer.stopTiming(); // Spigot
 
         gameprofilerfiller.popPush("send chunks");
         iterator = this.playerList.getPlayers().iterator();
@@ -1267,6 +1648,22 @@
         return (ServerLevel) this.levels.get(key);
     }
 
+    // CraftBukkit start
+    public void addLevel(ServerLevel level) {
+        Map<ResourceKey<Level>, ServerLevel> oldLevels = this.levels;
+        Map<ResourceKey<Level>, ServerLevel> newLevels = Maps.newLinkedHashMap(oldLevels);
+        newLevels.put(level.dimension(), level);
+        this.levels = Collections.unmodifiableMap(newLevels);
+    }
+
+    public void removeLevel(ServerLevel level) {
+        Map<ResourceKey<Level>, ServerLevel> oldLevels = this.levels;
+        Map<ResourceKey<Level>, ServerLevel> newLevels = Maps.newLinkedHashMap(oldLevels);
+        newLevels.remove(level.dimension());
+        this.levels = Collections.unmodifiableMap(newLevels);
+    }
+    // CraftBukkit end
+
     public Set<ResourceKey<Level>> levelKeys() {
         return this.levels.keySet();
     }
@@ -1296,7 +1693,7 @@
 
     @DontObfuscate
     public String getServerModName() {
-        return "vanilla";
+        return "Spigot"; // Spigot - Spigot > // CraftBukkit - cb > vanilla!
     }
 
     public SystemReport fillSystemReport(SystemReport details) {
@@ -1481,10 +1878,20 @@
 
     @Override
     public String getMotd() {
-        return this.motd;
+        return net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer.legacySection().serialize(this.motd); // Paper - Adventure
     }
 
     public void setMotd(String motd) {
+        // Paper start - Adventure
+        this.motd = net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer.legacySection().deserializeOr(motd, net.kyori.adventure.text.Component.empty());
+    }
+
+    public net.kyori.adventure.text.Component motd() {
+        return this.motd;
+    }
+
+    public void motd(net.kyori.adventure.text.Component motd) {
+        // Paper end - Adventure
         this.motd = motd;
     }
 
@@ -1507,7 +1914,7 @@
     }
 
     public ServerConnectionListener getConnection() {
-        return this.connection;
+        return this.connection == null ? this.connection = new ServerConnectionListener(this) : this.connection; // Spigot
     }
 
     public boolean isReady() {
@@ -1634,11 +2041,11 @@
 
     public CompletableFuture<Void> reloadResources(Collection<String> dataPacks) {
         CompletableFuture<Void> completablefuture = CompletableFuture.supplyAsync(() -> {
-            Stream stream = dataPacks.stream();
+            Stream<String> stream = dataPacks.stream(); // CraftBukkit - decompile error
             PackRepository resourcepackrepository = this.packRepository;
 
             Objects.requireNonNull(this.packRepository);
-            return (ImmutableList) stream.map(resourcepackrepository::getPack).filter(Objects::nonNull).map(Pack::open).collect(ImmutableList.toImmutableList());
+            return stream.<Pack>map(resourcepackrepository::getPack).filter(Objects::nonNull).map(Pack::open).collect(ImmutableList.toImmutableList()); // CraftBukkit - decompile error // Paper - decompile error // todo: is this needed anymore?
         }, this).thenCompose((immutablelist) -> {
             MultiPackResourceManager resourcemanager = new MultiPackResourceManager(PackType.SERVER_DATA, immutablelist);
             List<Registry.PendingTags<?>> list = TagLoader.loadTagsForExistingRegistries(resourcemanager, this.registries.compositeAccess());
@@ -1654,6 +2061,7 @@
         }).thenAcceptAsync((minecraftserver_reloadableresources) -> {
             this.resources.close();
             this.resources = minecraftserver_reloadableresources;
+            this.server.syncCommands(); // SPIGOT-5884: Lost on reload
             this.packRepository.setSelected(dataPacks);
             WorldDataConfiguration worlddataconfiguration = new WorldDataConfiguration(MinecraftServer.getSelectedPacks(this.packRepository, true), this.worldData.enabledFeatures());
 
@@ -1952,7 +2360,7 @@
             final List<String> list = Lists.newArrayList();
             final GameRules gamerules = this.getGameRules();
 
-            gamerules.visitGameRuleTypes(new GameRules.GameRuleTypeVisitor(this) {
+            gamerules.visitGameRuleTypes(new GameRules.GameRuleTypeVisitor() { // CraftBukkit - decompile error
                 @Override
                 public <T extends GameRules.Value<T>> void visit(GameRules.Key<T> key, GameRules.Type<T> type) {
                     list.add(String.format(Locale.ROOT, "%s=%s\n", key.getId(), gamerules.getRule(key)));
@@ -2058,7 +2466,7 @@
             try {
                 label51:
                 {
-                    ArrayList arraylist;
+                    ArrayList<NativeModuleLister.NativeModuleInfo> arraylist; // CraftBukkit - decompile error
 
                     try {
                         arraylist = Lists.newArrayList(NativeModuleLister.listModules());
@@ -2105,9 +2513,25 @@
         if (bufferedwriter != null) {
             bufferedwriter.close();
         }
+
+    }
 
+    // CraftBukkit start
+    public boolean isDebugging() {
+        return false;
     }
 
+    @Deprecated
+    public static MinecraftServer getServer() {
+        return (Bukkit.getServer() instanceof CraftServer) ? ((CraftServer) Bukkit.getServer()).getServer() : null;
+    }
+
+    @Deprecated
+    public static RegistryAccess getDefaultRegistryAccess() {
+        return CraftRegistry.getMinecraftRegistry();
+    }
+    // CraftBukkit end
+
     private ProfilerFiller createProfiler() {
         if (this.willStartRecordingMetrics) {
             this.metricsRecorder = ActiveMetricsRecorder.createStarted(new ServerMetricsSamplersProvider(Util.timeSource, this.isDedicatedServer()), Util.timeSource, Util.ioPool(), new MetricsPersister("server"), this.onMetricsRecordingStopped, (path) -> {
@@ -2225,18 +2649,24 @@
     }
 
     public void logChatMessage(Component message, ChatType.Bound params, @Nullable String prefix) {
-        String s1 = params.decorate(message).getString();
+        // Paper start
+        net.kyori.adventure.text.Component s1 = io.papermc.paper.adventure.PaperAdventure.asAdventure(params.decorate(message));
 
         if (prefix != null) {
-            MinecraftServer.LOGGER.info("[{}] {}", prefix, s1);
+            MinecraftServer.COMPONENT_LOGGER.info("[{}] {}", prefix, s1);
         } else {
-            MinecraftServer.LOGGER.info("{}", s1);
+            MinecraftServer.COMPONENT_LOGGER.info("{}", s1);
+            // Paper end
         }
 
     }
 
+    public final java.util.concurrent.ExecutorService chatExecutor = java.util.concurrent.Executors.newCachedThreadPool(
+            new com.google.common.util.concurrent.ThreadFactoryBuilder().setDaemon(true).setNameFormat("Async Chat Thread - #%d").setUncaughtExceptionHandler(new net.minecraft.DefaultUncaughtExceptionHandlerWithName(net.minecraft.server.MinecraftServer.LOGGER)).build()); // Paper
+
+    public final ChatDecorator improvedChatDecorator = new io.papermc.paper.adventure.ImprovedChatDecorator(this); // Paper - adventure
     public ChatDecorator getChatDecorator() {
-        return ChatDecorator.PLAIN;
+        return this.improvedChatDecorator; // Paper - support async chat decoration events
     }
 
     public boolean logIPs() {