--- a/net/minecraft/server/MinecraftServer.java
+++ b/net/minecraft/server/MinecraftServer.java
@@ -56,6 +56,13 @@
 import org.apache.commons.lang3.Validate;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+// CraftBukkit start
+import jline.console.ConsoleReader;
+import org.bukkit.Bukkit;
+import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.craftbukkit.Main;
+import org.bukkit.event.server.ServerLoadEvent;
+// CraftBukkit end
 
 public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTask> implements IMojangStatistics, ICommandListener, AutoCloseable, Runnable {
 
@@ -75,7 +82,7 @@
     public final DataFixer dataConverterManager;
     private String serverIp;
     private int serverPort = -1;
-    public final Map<DimensionManager, WorldServer> worldServer = Maps.newIdentityHashMap();
+    public final Map<DimensionManager, WorldServer> worldServer = Maps.newLinkedHashMap(); // CraftBukkit - keep order, k+v already use identity methods
     private PlayerList playerList;
     private volatile boolean isRunning = true;
     private boolean isStopped;
@@ -113,7 +120,7 @@
     private final GameProfileRepository gameProfileRepository;
     private final UserCache userCache;
     private long Z;
-    public final Thread serverThread = (Thread) SystemUtils.a((Object) (new Thread(this, "Server thread")), (thread) -> {
+    public final Thread serverThread = (Thread) SystemUtils.a((new Thread(this, "Server thread")), (thread) -> { // CraftBukkit - decompile error
         thread.setUncaughtExceptionHandler((thread1, throwable) -> {
             MinecraftServer.LOGGER.error(throwable);
         });
@@ -145,7 +152,21 @@
     @Nullable
     private String ax;
 
-    public MinecraftServer(File file, Proxy proxy, DataFixer datafixer, CommandDispatcher commanddispatcher, YggdrasilAuthenticationService yggdrasilauthenticationservice, MinecraftSessionService minecraftsessionservice, GameProfileRepository gameprofilerepository, UserCache usercache, WorldLoadListenerFactory worldloadlistenerfactory, String s) {
+    // CraftBukkit start
+    public org.bukkit.craftbukkit.CraftServer server;
+    public OptionSet options;
+    public org.bukkit.command.ConsoleCommandSender console;
+    public org.bukkit.command.RemoteConsoleCommandSender remoteConsole;
+    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 File bukkitDataPackFolder;
+    public CommandDispatcher vanillaCommandDispatcher;
+    private boolean forceTicks;
+    // CraftBukkit end
+
+    public MinecraftServer(OptionSet options, Proxy proxy, DataFixer datafixer, CommandDispatcher commanddispatcher, YggdrasilAuthenticationService yggdrasilauthenticationservice, MinecraftSessionService minecraftsessionservice, GameProfileRepository gameprofilerepository, UserCache usercache, WorldLoadListenerFactory worldloadlistenerfactory, String s) {
         super("Server");
         this.ae = new ResourceManager(EnumResourcePackType.SERVER_DATA, this.serverThread);
         this.resourcePackRepository = new ResourcePackRepository<>(ResourcePackLoader::new);
@@ -159,15 +180,15 @@
         this.customFunctionData = new CustomFunctionData(this);
         this.circularTimer = new CircularTimer();
         this.proxy = proxy;
-        this.commandDispatcher = commanddispatcher;
+        this.commandDispatcher = this.vanillaCommandDispatcher = commanddispatcher; // CraftBukkit
         this.yggdrasilAuthenticationService = yggdrasilauthenticationservice;
         this.minecraftSessionService = minecraftsessionservice;
         this.gameProfileRepository = gameprofilerepository;
         this.userCache = usercache;
-        this.universe = file;
-        this.serverConnection = new ServerConnection(this);
+        // this.universe = file; // CraftBukkit
+        this.serverConnection = new ServerConnection(this); // CraftBukkit
         this.worldLoadListenerFactory = worldloadlistenerfactory;
-        this.convertable = new Convertable(file.toPath(), file.toPath().resolve("../backups"), datafixer);
+        // this.convertable = new Convertable(file.toPath(), file.toPath().resolve("../backups"), datafixer); // CraftBukkit - moved to DedicatedServer.init
         this.dataConverterManager = datafixer;
         this.ae.a((IReloadListener) this.tagRegistry);
         this.ae.a((IReloadListener) this.lootPredicateManager);
@@ -177,7 +198,32 @@
         this.ae.a((IReloadListener) this.advancementDataWorld);
         this.executorService = SystemUtils.e();
         this.K = s;
+        // CraftBukkit start
+        this.options = options;
+        // 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 {
+            reader = new ConsoleReader(System.in, System.out);
+            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;
+                reader = new ConsoleReader(System.in, System.out);
+                reader.setExpandEvents(false);
+            } catch (IOException ex) {
+                LOGGER.warn((String) null, ex);
+            }
+        }
+        Runtime.getRuntime().addShutdownHook(new org.bukkit.craftbukkit.util.ServerShutdownThread(this));
     }
+    // CraftBukkit end
 
     private void initializeScoreboards(WorldPersistentData worldpersistentdata) {
         PersistentScoreboard persistentscoreboard = (PersistentScoreboard) worldpersistentdata.a(PersistentScoreboard::new, "scoreboard");
@@ -213,11 +259,11 @@
         }
 
         if (this.forceUpgrade) {
-            MinecraftServer.LOGGER.info("Forcing world upgrade!");
-            WorldData worlddata = this.getConvertable().b(this.getWorld());
+            MinecraftServer.LOGGER.info("Forcing world upgrade! {}", s); // CraftBukkit
+            WorldData worlddata = this.getConvertable().b(s); // CraftBukkit
 
             if (worlddata != null) {
-                WorldUpgrader worldupgrader = new WorldUpgrader(this.getWorld(), this.getConvertable(), worlddata, this.eraseCache);
+                WorldUpgrader worldupgrader = new WorldUpgrader(s, this.getConvertable(), worlddata, this.eraseCache); // CraftBukkit
                 IChatBaseComponent ichatbasecomponent = null;
 
                 while (!worldupgrader.b()) {
@@ -256,8 +302,9 @@
     }
 
     protected void a(String s, String s1, long i, WorldType worldtype, JsonElement jsonelement) {
-        this.convertWorld(s);
+        // this.convertWorld(s); // CraftBukkit - moved down
         this.b((IChatBaseComponent) (new ChatMessage("menu.loadingLevel", new Object[0])));
+        /* CraftBukkit start - Remove ticktime arrays and worldsettings
         WorldNBTStorage worldnbtstorage = this.getConvertable().a(s, this);
 
         this.a(this.getWorld(), worldnbtstorage);
@@ -283,27 +330,137 @@
 
         worlddata.a(this.getServerModName(), this.q().isPresent());
         this.a(worldnbtstorage.getDirectory(), worlddata);
-        WorldLoadListener worldloadlistener = this.worldLoadListenerFactory.create(11);
+        */
+        int worldCount = 3;
 
-        this.a(worldnbtstorage, worlddata, worldsettings, worldloadlistener);
-        this.a(this.getDifficulty(), true);
-        this.loadSpawn(worldloadlistener);
-    }
+        for (int j = 0; j < worldCount; ++j) {
+            WorldServer world;
+            WorldData worlddata;
+            byte dimension = 0;
+
+            if (j == 1) {
+                if (getAllowNether()) {
+                    dimension = -1;
+                } else {
+                    continue;
+                }
+            }
 
-    protected void a(WorldNBTStorage worldnbtstorage, WorldData worlddata, WorldSettings worldsettings, WorldLoadListener worldloadlistener) {
-        if (this.isDemoMode()) {
-            worlddata.a(MinecraftServer.c);
+            if (j == 2) {
+                if (server.getAllowEnd()) {
+                    dimension = 1;
+                } else {
+                    continue;
+                }
+            }
+
+            String worldType = org.bukkit.World.Environment.getEnvironment(dimension).toString().toLowerCase();
+            String name = (dimension == 0) ? s : s + "_" + worldType;
+            this.convertWorld(name); // Run conversion now
+
+            org.bukkit.generator.ChunkGenerator gen = this.server.getGenerator(name);
+            WorldSettings worldsettings = new WorldSettings(i, this.getGamemode(), this.getGenerateStructures(), this.isHardcore(), worldtype);
+            worldsettings.setGeneratorSettings(jsonelement);
+
+            if (j == 0) {
+                WorldNBTStorage worldnbtstorage = new WorldNBTStorage(server.getWorldContainer(), s1, this, this.dataConverterManager);
+                worlddata = worldnbtstorage.getWorldData();
+                if (worlddata == null) {
+                    worlddata = new WorldData(worldsettings, s1);
+                }
+                worlddata.checkName(s1); // 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)
+                this.a(worldnbtstorage.getDirectory(), worlddata);
+                WorldLoadListener worldloadlistener = this.worldLoadListenerFactory.create(11);
+
+                if (this.isDemoMode()) {
+                    worlddata.a(MinecraftServer.c);
+                }
+                world = new WorldServer(this, this.executorService, worldnbtstorage, worlddata, DimensionManager.OVERWORLD, this.methodProfiler, worldloadlistener, org.bukkit.World.Environment.getEnvironment(dimension), gen);
+
+                WorldPersistentData worldpersistentdata = world.getWorldPersistentData();
+                this.initializeScoreboards(worldpersistentdata);
+                this.server.scoreboardManager = new org.bukkit.craftbukkit.scoreboard.CraftScoreboardManager(this, world.getScoreboard());
+                this.persistentCommandStorage = new PersistentCommandStorage(worldpersistentdata);
+            } else {
+                String dim = "DIM" + dimension;
+
+                File newWorld = new File(new File(name), dim);
+                File oldWorld = new File(new File(s), dim);
+                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 ----");
+                    }
+                }
+
+                WorldNBTStorage worldnbtstorage = new WorldNBTStorage(server.getWorldContainer(), name, this, this.dataConverterManager);
+                // world =, b0 to dimension, s1 to name, added Environment and gen
+                worlddata = worldnbtstorage.getWorldData();
+                if (worlddata == null) {
+                    worlddata = new WorldData(worldsettings, name);
+                }
+                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)
+                WorldLoadListener worldloadlistener = this.worldLoadListenerFactory.create(11);
+                world = new SecondaryWorldServer(this.getWorldServer(DimensionManager.OVERWORLD), this, this.executorService, worldnbtstorage, DimensionManager.a(dimension), this.methodProfiler, worldloadlistener, worlddata, org.bukkit.World.Environment.getEnvironment(dimension), gen);
+            }
+
+            this.initWorld(world, worlddata, worldsettings);
+            this.server.getPluginManager().callEvent(new org.bukkit.event.world.WorldInitEvent(world.getWorld()));
+
+            this.worldServer.put(world.getWorldProvider().getDimensionManager(), world);
+            this.getPlayerList().setPlayerFileData(world);
+
+            if (worlddata.getCustomBossEvents() != null) {
+                this.getBossBattleCustomData().load(worlddata.getCustomBossEvents());
+            }
+        }
+        this.a(this.getDifficulty(), true);
+        for (WorldServer worldserver : this.getWorlds()) {
+            this.loadSpawn(worldserver.getChunkProvider().playerChunkMap.worldLoadListener, worldserver);
+            this.server.getPluginManager().callEvent(new org.bukkit.event.world.WorldLoadEvent(worldserver.getWorld()));
         }
 
-        WorldServer worldserver = new WorldServer(this, this.executorService, worldnbtstorage, worlddata, DimensionManager.OVERWORLD, this.methodProfiler, worldloadlistener);
+        this.server.enablePlugins(org.bukkit.plugin.PluginLoadOrder.POSTWORLD);
+        this.server.getPluginManager().callEvent(new ServerLoadEvent(ServerLoadEvent.LoadType.STARTUP));
+        this.serverConnection.acceptConnections();
+        // CraftBukkit end
 
-        this.worldServer.put(DimensionManager.OVERWORLD, worldserver);
-        WorldPersistentData worldpersistentdata = worldserver.getWorldPersistentData();
+    }
 
-        this.initializeScoreboards(worldpersistentdata);
-        this.persistentCommandStorage = new PersistentCommandStorage(worldpersistentdata);
-        worldserver.getWorldBorder().b(worlddata);
-        WorldServer worldserver1 = this.getWorldServer(DimensionManager.OVERWORLD);
+    // CraftBukkit start
+    public void initWorld(WorldServer worldserver1, WorldData worlddata, WorldSettings worldsettings) {
+        worldserver1.getWorldBorder().b(worlddata);
+
+        // CraftBukkit start
+        if (worldserver1.generator != null) {
+            worldserver1.getWorld().getPopulators().addAll(worldserver1.generator.getDefaultPopulators(worldserver1.getWorld()));
+        }
+        // CraftBukkit end
 
         if (!worlddata.u()) {
             try {
@@ -327,23 +484,8 @@
 
             worlddata.d(true);
         }
-
-        this.getPlayerList().setPlayerFileData(worldserver1);
-        if (worlddata.getCustomBossEvents() != null) {
-            this.getBossBattleCustomData().load(worlddata.getCustomBossEvents());
-        }
-
-        Iterator iterator = DimensionManager.a().iterator();
-
-        while (iterator.hasNext()) {
-            DimensionManager dimensionmanager = (DimensionManager) iterator.next();
-
-            if (dimensionmanager != DimensionManager.OVERWORLD) {
-                this.worldServer.put(dimensionmanager, new SecondaryWorldServer(worldserver1, this, this.executorService, worldnbtstorage, dimensionmanager, this.methodProfiler, worldloadlistener));
-            }
-        }
-
     }
+    // CraftBukkit end
 
     private void a(WorldData worlddata) {
         worlddata.f(false);
@@ -362,6 +504,23 @@
     protected void a(File file, WorldData worlddata) {
         this.resourcePackRepository.a((ResourcePackSource) (new ResourcePackSourceVanilla()));
         this.resourcePackFolder = new ResourcePackSourceFolder(new File(file, "datapacks"));
+        // CraftBukkit start
+        bukkitDataPackFolder = new File(new File(file, "datapacks"), "bukkit");
+        if (!bukkitDataPackFolder.exists()) {
+            bukkitDataPackFolder.mkdirs();
+        }
+        File mcMeta = new File(bukkitDataPackFolder, "pack.mcmeta");
+        try {
+            com.google.common.io.Files.write("{\n"
+                    + "    \"pack\": {\n"
+                    + "        \"description\": \"Data pack for resources provided by Bukkit plugins\",\n"
+                    + "        \"pack_format\": " + SharedConstants.getGameVersion().getPackVersion() + "\n"
+                    + "    }\n"
+                    + "}\n", mcMeta, com.google.common.base.Charsets.UTF_8);
+        } catch (IOException ex) {
+            throw new RuntimeException("Could not initialize Bukkit datapack", ex);
+        }
+        // CraftBukkit end
         this.resourcePackRepository.a((ResourcePackSource) this.resourcePackFolder);
         this.resourcePackRepository.a();
         List<ResourcePackLoader> list = Lists.newArrayList();
@@ -383,11 +542,18 @@
         this.bb();
     }
 
-    public void loadSpawn(WorldLoadListener worldloadlistener) {
+    // CraftBukkit start
+    public void loadSpawn(WorldLoadListener worldloadlistener, WorldServer worldserver) {
+        if (!worldserver.getWorld().getKeepSpawnInMemory()) {
+            return;
+        }
+
         this.b((IChatBaseComponent) (new ChatMessage("menu.generatingTerrain", new Object[0])));
-        WorldServer worldserver = this.getWorldServer(DimensionManager.OVERWORLD);
+        // WorldServer worldserver = this.getWorldServer(DimensionManager.OVERWORLD);
+        this.forceTicks = true;
+        // CraftBukkit end
 
-        MinecraftServer.LOGGER.info("Preparing start region for dimension " + DimensionManager.a(worldserver.worldProvider.getDimensionManager()));
+        MinecraftServer.LOGGER.info("Preparing start region for dimension '{}'/{}", worldserver.getWorldData().getName(), DimensionManager.a(worldserver.worldProvider.getDimensionManager().getType())); // CraftBukkit
         BlockPosition blockposition = worldserver.getSpawn();
 
         worldloadlistener.a(new ChunkCoordIntPair(blockposition));
@@ -398,17 +564,21 @@
         chunkproviderserver.addTicket(TicketType.START, new ChunkCoordIntPair(blockposition), 11, Unit.INSTANCE);
 
         while (chunkproviderserver.b() != 441) {
-            this.nextTick = SystemUtils.getMonotonicMillis() + 10L;
-            this.sleepForTick();
+            // CraftBukkit start
+            // this.nextTick = SystemUtils.getMonotonicMillis() + 10L;
+            this.executeModerately();
+            // CraftBukkit end
         }
 
-        this.nextTick = SystemUtils.getMonotonicMillis() + 10L;
-        this.sleepForTick();
-        Iterator iterator = DimensionManager.a().iterator();
-
-        while (iterator.hasNext()) {
-            DimensionManager dimensionmanager = (DimensionManager) iterator.next();
-            ForcedChunk forcedchunk = (ForcedChunk) this.getWorldServer(dimensionmanager).getWorldPersistentData().b(ForcedChunk::new, "chunks");
+        // CraftBukkit start
+        // this.nextTick = SystemUtils.getMonotonicMillis() + 10L;
+        this.executeModerately();
+        // Iterator iterator = DimensionManager.a().iterator();
+
+        if (true) {
+            DimensionManager dimensionmanager = worldserver.worldProvider.getDimensionManager();
+            ForcedChunk forcedchunk = (ForcedChunk) worldserver.getWorldPersistentData().b(ForcedChunk::new, "chunks");
+            // CraftBukkit end
 
             if (forcedchunk != null) {
                 WorldServer worldserver1 = this.getWorldServer(dimensionmanager);
@@ -423,10 +593,16 @@
             }
         }
 
-        this.nextTick = SystemUtils.getMonotonicMillis() + 10L;
-        this.sleepForTick();
+        // CraftBukkit start
+        // this.nextTick = SystemUtils.getMonotonicMillis() + 10L;
+        this.executeModerately();
+        // CraftBukkit end
         worldloadlistener.b();
         chunkproviderserver.getLightEngine().a(5);
+
+        // CraftBukkit start
+        this.forceTicks = false;
+        // CraftBukkit end
     }
 
     protected void a(String s, WorldNBTStorage worldnbtstorage) {
@@ -473,12 +649,16 @@
             }
         }
 
+        // CraftBukkit start - moved to WorldServer.save
+        /*
         WorldServer worldserver1 = this.getWorldServer(DimensionManager.OVERWORLD);
         WorldData worlddata = worldserver1.getWorldData();
 
         worldserver1.getWorldBorder().save(worlddata);
         worlddata.setCustomBossEvents(this.getBossBattleCustomData().save());
         worldserver1.getDataManager().saveWorldData(worlddata, this.getPlayerList().save());
+        */
+        // CraftBukkit end
         return flag3;
     }
 
@@ -487,8 +667,29 @@
         this.stop();
     }
 
+    // CraftBukkit start
+    private boolean hasStopped = false;
+    private final Object stopLock = new Object();
+    public final boolean hasStopped() {
+        synchronized (stopLock) {
+            return hasStopped;
+        }
+    }
+    // CraftBukkit end
+
     protected void stop() {
+        // CraftBukkit start - prevent double stopping on multiple threads
+        synchronized(stopLock) {
+            if (hasStopped) return;
+            hasStopped = true;
+        }
+        // CraftBukkit end
         MinecraftServer.LOGGER.info("Stopping server");
+        // CraftBukkit start
+        if (this.server != null) {
+            this.server.disablePlugins();
+        }
+        // CraftBukkit end
         if (this.getServerConnection() != null) {
             this.getServerConnection().b();
         }
@@ -497,6 +698,7 @@
             MinecraftServer.LOGGER.info("Saving players");
             this.playerList.savePlayers();
             this.playerList.shutdown();
+            try { Thread.sleep(100); } catch (InterruptedException ex) {} // CraftBukkit - SPIGOT-625 - give server at least a chance to send packets
         }
 
         MinecraftServer.LOGGER.info("Saving worlds");
@@ -566,14 +768,16 @@
                 while (this.isRunning) {
                     long i = SystemUtils.getMonotonicMillis() - this.nextTick;
 
-                    if (i > 2000L && this.nextTick - this.lastOverloadTime >= 15000L) {
+                    if (i > 5000L && this.nextTick - this.lastOverloadTime >= 30000L) { // CraftBukkit
                         long j = i / 50L;
 
+                        if (server.getWarnOnOverload()) // CraftBukkit
                         MinecraftServer.LOGGER.warn("Can't keep up! Is the server overloaded? Running {}ms or {} ticks behind", i, j);
                         this.nextTick += j * 50L;
                         this.lastOverloadTime = this.nextTick;
                     }
 
+                    MinecraftServer.currentTick = (int) (System.currentTimeMillis() / 50); // CraftBukkit
                     this.nextTick += 50L;
                     if (this.T) {
                         this.T = false;
@@ -620,6 +824,12 @@
             } catch (Throwable throwable1) {
                 MinecraftServer.LOGGER.error("Exception stopping the server", throwable1);
             } finally {
+                // CraftBukkit start - Restore terminal to original settings
+                try {
+                    reader.getTerminal().restore();
+                } catch (Exception ignored) {
+                }
+                // CraftBukkit end
                 this.exit();
             }
 
@@ -628,8 +838,15 @@
     }
 
     private boolean canSleepForTick() {
-        return this.isEntered() || SystemUtils.getMonotonicMillis() < (this.ac ? this.ab : this.nextTick);
+        // CraftBukkit start
+        return this.forceTicks || this.isEntered() || SystemUtils.getMonotonicMillis() < (this.ac ? this.ab : this.nextTick);
+    }
+
+    private void executeModerately() {
+        this.executeAll();
+        java.util.concurrent.locks.LockSupport.parkNanos("executing tasks", 1000L);
     }
+    // CraftBukkit end
 
     protected void sleepForTick() {
         this.executeAll();
@@ -735,7 +952,7 @@
             this.serverPing.b().a(agameprofile);
         }
 
-        if (this.ticks % 6000 == 0) {
+        if (autosavePeriod > 0 && this.ticks % autosavePeriod == 0) { // CraftBukkit
             MinecraftServer.LOGGER.debug("Autosave started");
             this.methodProfiler.enter("save");
             this.playerList.savePlayers();
@@ -765,23 +982,40 @@
     }
 
     protected void b(BooleanSupplier booleansupplier) {
+        this.server.getScheduler().mainThreadHeartbeat(this.ticks); // CraftBukkit
         this.methodProfiler.enter("commandFunctions");
         this.getFunctionData().tick();
         this.methodProfiler.exitEnter("levels");
         Iterator iterator = this.getWorlds().iterator();
 
+        // CraftBukkit start
+        // Run tasks that are waiting on processing
+        while (!processQueue.isEmpty()) {
+            processQueue.remove().run();
+        }
+
+        // Send time updates to everyone, it will get the right time from the world the player is in.
+        if (this.ticks % 20 == 0) {
+            for (int i = 0; i < this.getPlayerList().players.size(); ++i) {
+                EntityPlayer entityplayer = (EntityPlayer) this.getPlayerList().players.get(i);
+                entityplayer.playerConnection.sendPacket(new PacketPlayOutUpdateTime(entityplayer.world.getTime(), entityplayer.getPlayerTime(), entityplayer.world.getGameRules().getBoolean(GameRules.DO_DAYLIGHT_CYCLE))); // Add support for per player time
+            }
+        }
+
         while (iterator.hasNext()) {
             WorldServer worldserver = (WorldServer) iterator.next();
 
-            if (worldserver.worldProvider.getDimensionManager() == DimensionManager.OVERWORLD || this.getAllowNether()) {
+            if (true || worldserver.worldProvider.getDimensionManager() == DimensionManager.OVERWORLD || this.getAllowNether()) { // CraftBukkit
                 this.methodProfiler.a(() -> {
                     return worldserver.getWorldData().getName() + " " + IRegistry.DIMENSION_TYPE.getKey(worldserver.worldProvider.getDimensionManager());
                 });
+                /* Drop global time updates
                 if (this.ticks % 20 == 0) {
                     this.methodProfiler.enter("timeSync");
                     this.playerList.a((Packet) (new PacketPlayOutUpdateTime(worldserver.getTime(), worldserver.getDayTime(), worldserver.getGameRules().getBoolean(GameRules.DO_DAYLIGHT_CYCLE))), worldserver.worldProvider.getDimensionManager());
                     this.methodProfiler.exit();
                 }
+                // CraftBukkit end */
 
                 this.methodProfiler.enter("tick");
 
@@ -824,7 +1058,8 @@
         this.tickables.add(runnable);
     }
 
-    public static void main(String[] astring) {
+    public static void main(final OptionSet optionset) { // CraftBukkit - replaces main(String[] astring)
+        /* CraftBukkit start - Replace everything
         OptionParser optionparser = new OptionParser();
         OptionSpec<Void> optionspec = optionparser.accepts("nogui");
         OptionSpec<Void> optionspec1 = optionparser.accepts("initSettings", "Initializes 'server.properties' and 'eula.txt', then quits");
@@ -847,15 +1082,17 @@
                 optionparser.printHelpOn(System.err);
                 return;
             }
+            */ // CraftBukkit end
 
+        try {
             java.nio.file.Path java_nio_file_path = Paths.get("server.properties");
-            DedicatedServerSettings dedicatedserversettings = new DedicatedServerSettings(java_nio_file_path);
+            DedicatedServerSettings dedicatedserversettings = new DedicatedServerSettings(optionset); // CraftBukkit - CLI argument support
 
             dedicatedserversettings.save();
             java.nio.file.Path java_nio_file_path1 = Paths.get("eula.txt");
             EULA eula = new EULA(java_nio_file_path1);
 
-            if (optionset.has(optionspec1)) {
+            if (optionset.has("initSettings")) { // CraftBukkit
                 MinecraftServer.LOGGER.info("Initialized '" + java_nio_file_path.toAbsolutePath().toString() + "' and '" + java_nio_file_path1.toAbsolutePath().toString() + "'");
                 return;
             }
@@ -868,14 +1105,16 @@
             CrashReport.h();
             DispenserRegistry.init();
             DispenserRegistry.c();
-            String s = (String) optionset.valueOf(optionspec8);
+            File s = (File) optionset.valueOf("universe"); // CraftBukkit
             YggdrasilAuthenticationService yggdrasilauthenticationservice = new YggdrasilAuthenticationService(Proxy.NO_PROXY, UUID.randomUUID().toString());
             MinecraftSessionService minecraftsessionservice = yggdrasilauthenticationservice.createMinecraftSessionService();
             GameProfileRepository gameprofilerepository = yggdrasilauthenticationservice.createProfileRepository();
             UserCache usercache = new UserCache(gameprofilerepository, new File(s, MinecraftServer.b.getName()));
-            String s1 = (String) Optional.ofNullable(optionset.valueOf(optionspec9)).orElse(dedicatedserversettings.getProperties().levelName);
-            final DedicatedServer dedicatedserver = new DedicatedServer(new File(s), dedicatedserversettings, DataConverterRegistry.a(), yggdrasilauthenticationservice, minecraftsessionservice, gameprofilerepository, usercache, WorldLoadListenerLogger::new, s1);
+            // CraftBukkit start
+            String s1 = (String) Optional.ofNullable(optionset.valueOf("world")).orElse(dedicatedserversettings.getProperties().levelName);
+            final DedicatedServer dedicatedserver = new DedicatedServer(optionset, dedicatedserversettings, DataConverterRegistry.a(), yggdrasilauthenticationservice, minecraftsessionservice, gameprofilerepository, usercache, WorldLoadListenerLogger::new, s1);
 
+            /*
             dedicatedserver.i((String) optionset.valueOf(optionspec7));
             dedicatedserver.setPort((Integer) optionset.valueOf(optionspec10));
             dedicatedserver.e(optionset.has(optionspec2));
@@ -883,12 +1122,14 @@
             dedicatedserver.setForceUpgrade(optionset.has(optionspec4));
             dedicatedserver.setEraseCache(optionset.has(optionspec5));
             dedicatedserver.c((String) optionset.valueOf(optionspec11));
-            boolean flag = !optionset.has(optionspec) && !optionset.valuesOf(nonoptionargumentspec).contains("nogui");
+            */
+            boolean flag = !optionset.has("nogui") && !optionset.nonOptionArguments().contains("nogui");
 
             if (flag && !GraphicsEnvironment.isHeadless()) {
                 dedicatedserver.bc();
             }
 
+            /*
             dedicatedserver.startServerThread();
             Thread thread = new Thread("Server Shutdown Thread") {
                 public void run() {
@@ -898,6 +1139,29 @@
 
             thread.setUncaughtExceptionHandler(new DefaultUncaughtExceptionHandler(MinecraftServer.LOGGER));
             Runtime.getRuntime().addShutdownHook(thread);
+            */
+
+            if (optionset.has("port")) {
+                int port = (Integer) optionset.valueOf("port");
+                if (port > 0) {
+                    dedicatedserver.setPort(port);
+                }
+            }
+
+            if (optionset.has("universe")) {
+                dedicatedserver.universe = (File) optionset.valueOf("universe");
+            }
+
+            if (optionset.has("forceUpgrade")) {
+                dedicatedserver.setForceUpgrade(true);
+            }
+
+            if (optionset.has("eraseCache")) {
+                dedicatedserver.setEraseCache(true);
+            }
+
+            dedicatedserver.serverThread.start();
+            // CraftBukkit end
         } catch (Exception exception) {
             MinecraftServer.LOGGER.fatal("Failed to start the minecraft server", exception);
         }
@@ -917,7 +1181,9 @@
     }
 
     public void startServerThread() {
+        /* CraftBukkit start - prevent abuse
         this.serverThread.start();
+        // CraftBukkit end */
     }
 
     public File d(String s) {
@@ -972,7 +1238,7 @@
     }
 
     public String getServerModName() {
-        return "vanilla";
+        return server.getName(); // CraftBukkit - cb > vanilla!
     }
 
     public CrashReport b(CrashReport crashreport) {
@@ -1013,7 +1279,7 @@
     public abstract Optional<String> q();
 
     public boolean K() {
-        return this.universe != null;
+        return true; // CraftBukkit
     }
 
     @Override
@@ -1729,4 +1995,16 @@
     private void bb() {
         Block.REGISTRY_ID.forEach(IBlockData::c);
     }
+
+    // CraftBukkit start
+    @Override
+    public boolean isMainThread() {
+        return super.isMainThread() || this.isStopped(); // CraftBukkit - MC-142590
+    }
+
+    @Deprecated
+    public static MinecraftServer getServer() {
+        return (Bukkit.getServer() instanceof CraftServer) ? ((CraftServer) Bukkit.getServer()).getServer() : null;
+    }
+    // CraftBukkit end
 }
