--- a/net/minecraft/server/World.java
+++ b/net/minecraft/server/World.java
@@ -14,6 +14,17 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.util.Supplier;
 
+// CraftBukkit start
+import java.util.HashMap;
+import java.util.Map;
+import org.bukkit.Bukkit;
+import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.block.CapturedBlockState;
+import org.bukkit.craftbukkit.block.data.CraftBlockData;
+import org.bukkit.event.block.BlockPhysicsEvent;
+// CraftBukkit end
+
 public abstract class World implements GeneratorAccess, AutoCloseable {
 
     protected static final Logger LOGGER = LogManager.getLogger();
@@ -40,7 +51,39 @@
     private final WorldBorder worldBorder;
     private final BiomeManager biomeManager;
 
-    protected World(WorldData worlddata, DimensionManager dimensionmanager, BiFunction<World, WorldProvider, IChunkProvider> bifunction, GameProfilerFiller gameprofilerfiller, boolean flag) {
+    // CraftBukkit start Added the following
+    private final CraftWorld world;
+    public boolean pvpMode;
+    public boolean keepSpawnInMemory = true;
+    public org.bukkit.generator.ChunkGenerator generator;
+
+    public boolean captureBlockStates = false;
+    public boolean captureTreeGeneration = false;
+    public Map<BlockPosition, CapturedBlockState> capturedBlockStates = new HashMap<>();
+    public Map<BlockPosition, TileEntity> capturedTileEntities = new HashMap<>();
+    public List<EntityItem> captureDrops;
+    public long ticksPerAnimalSpawns;
+    public long ticksPerMonsterSpawns;
+    public boolean populating;
+
+    public CraftWorld getWorld() {
+        return this.world;
+    }
+
+    public CraftServer getServer() {
+        return (CraftServer) Bukkit.getServer();
+    }
+
+    public Chunk getChunkIfLoaded(int x, int z) {
+        return ((ChunkProviderServer) this.chunkProvider).getChunkAt(x, z, false);
+    }
+
+    protected World(WorldData worlddata, DimensionManager dimensionmanager, BiFunction<World, WorldProvider, IChunkProvider> bifunction, GameProfilerFiller gameprofilerfiller, boolean flag, org.bukkit.generator.ChunkGenerator gen, org.bukkit.World.Environment env) {
+        this.generator = gen;
+        this.world = new CraftWorld((WorldServer) this, gen, env);
+        this.ticksPerAnimalSpawns = this.getServer().getTicksPerAnimalSpawns(); // CraftBukkit
+        this.ticksPerMonsterSpawns = this.getServer().getTicksPerMonsterSpawns(); // CraftBukkit
+        // CraftBukkit end
         this.methodProfiler = gameprofilerfiller;
         this.worldData = worlddata;
         this.worldProvider = dimensionmanager.getWorldProvider(this);
@@ -49,6 +92,35 @@
         this.worldBorder = this.worldProvider.getWorldBorder();
         this.serverThread = Thread.currentThread();
         this.biomeManager = new BiomeManager(this, flag ? worlddata.getSeed() : WorldData.c(worlddata.getSeed()), dimensionmanager.getGenLayerZoomer());
+        // CraftBukkit start
+        getWorldBorder().world = (WorldServer) this;
+        // From PlayerList.setPlayerFileData
+        getWorldBorder().a(new IWorldBorderListener() {
+            public void a(WorldBorder worldborder, double d0) {
+                getServer().getHandle().sendAll(new PacketPlayOutWorldBorder(worldborder, PacketPlayOutWorldBorder.EnumWorldBorderAction.SET_SIZE), worldborder.world);
+            }
+
+            public void a(WorldBorder worldborder, double d0, double d1, long i) {
+                getServer().getHandle().sendAll(new PacketPlayOutWorldBorder(worldborder, PacketPlayOutWorldBorder.EnumWorldBorderAction.LERP_SIZE), worldborder.world);
+            }
+
+            public void a(WorldBorder worldborder, double d0, double d1) {
+                getServer().getHandle().sendAll(new PacketPlayOutWorldBorder(worldborder, PacketPlayOutWorldBorder.EnumWorldBorderAction.SET_CENTER), worldborder.world);
+            }
+
+            public void a(WorldBorder worldborder, int i) {
+                getServer().getHandle().sendAll(new PacketPlayOutWorldBorder(worldborder, PacketPlayOutWorldBorder.EnumWorldBorderAction.SET_WARNING_TIME), worldborder.world);
+            }
+
+            public void b(WorldBorder worldborder, int i) {
+                getServer().getHandle().sendAll(new PacketPlayOutWorldBorder(worldborder, PacketPlayOutWorldBorder.EnumWorldBorderAction.SET_WARNING_BLOCKS), worldborder.world);
+            }
+
+            public void b(WorldBorder worldborder, double d0) {}
+
+            public void c(WorldBorder worldborder, double d0) {}
+        });
+        // CraftBukkit end
     }
 
     @Override
@@ -105,6 +177,17 @@
 
     @Override
     public boolean setTypeAndData(BlockPosition blockposition, IBlockData iblockdata, int i) {
+        // CraftBukkit start - tree generation
+        if (this.captureTreeGeneration) {
+            CapturedBlockState blockstate = capturedBlockStates.get(blockposition);
+            if (blockstate == null) {
+                blockstate = CapturedBlockState.getTreeBlockState(this, blockposition, i);
+                this.capturedBlockStates.put(blockposition.immutableCopy(), blockstate);
+            }
+            blockstate.setData(iblockdata);
+            return true;
+        }
+        // CraftBukkit end
         if (isOutsideWorld(blockposition)) {
             return false;
         } else if (!this.isClientSide && this.worldData.getType() == WorldType.DEBUG_ALL_BLOCK_STATES) {
@@ -112,9 +195,22 @@
         } else {
             Chunk chunk = this.getChunkAtWorldCoords(blockposition);
             Block block = iblockdata.getBlock();
-            IBlockData iblockdata1 = chunk.setType(blockposition, iblockdata, (i & 64) != 0);
+
+            // CraftBukkit start - capture blockstates
+            if (this.captureBlockStates && !this.capturedBlockStates.containsKey(blockposition)) {
+                CapturedBlockState blockstate = CapturedBlockState.getBlockState(this, blockposition, i);
+                this.capturedBlockStates.put(blockposition.immutableCopy(), blockstate);
+            }
+            // CraftBukkit end
+
+            IBlockData iblockdata1 = chunk.setType(blockposition, iblockdata, (i & 64) != 0, (i & 1024) == 0); // CraftBukkit custom NO_PLACE flag
 
             if (iblockdata1 == null) {
+                // CraftBukkit start - remove blockstate if failed
+                if (this.captureBlockStates) {
+                    this.capturedBlockStates.remove(blockposition);
+                }
+                // CraftBukkit end
                 return false;
             } else {
                 IBlockData iblockdata2 = this.getType(blockposition);
@@ -125,6 +221,7 @@
                     this.methodProfiler.exit();
                 }
 
+                /*
                 if (iblockdata2 == iblockdata) {
                     if (iblockdata1 != iblockdata2) {
                         this.b(blockposition, iblockdata1, iblockdata2);
@@ -151,12 +248,65 @@
 
                     this.a(blockposition, iblockdata1, iblockdata2);
                 }
+                */
+
+                // CraftBukkit start
+                if (!this.captureBlockStates) { // Don't notify clients or update physics while capturing blockstates
+                    // Modularize client and physic updates
+                    notifyAndUpdatePhysics(blockposition, chunk, iblockdata1, iblockdata, iblockdata2, i);
+                }
+                // CraftBukkit end
 
                 return true;
             }
         }
     }
 
+    // CraftBukkit start - Split off from above in order to directly send client and physic updates
+    public void notifyAndUpdatePhysics(BlockPosition blockposition, Chunk chunk, IBlockData oldBlock, IBlockData newBlock, IBlockData actualBlock, int i) {
+        IBlockData iblockdata = newBlock;
+        IBlockData iblockdata1 = oldBlock;
+        IBlockData iblockdata2 = actualBlock;
+        if (iblockdata2 == iblockdata) {
+            if (iblockdata1 != iblockdata2) {
+                this.b(blockposition, iblockdata1, iblockdata2);
+            }
+
+            if ((i & 2) != 0 && (!this.isClientSide || (i & 4) == 0) && (this.isClientSide || chunk == null || (chunk.getState() != null && chunk.getState().isAtLeast(PlayerChunk.State.TICKING)))) { // allow chunk to be null here as chunk.isReady() is false when we send our notification during block placement
+                this.notify(blockposition, iblockdata1, iblockdata, i);
+            }
+
+            if (!this.isClientSide && (i & 1) != 0) {
+                this.update(blockposition, iblockdata1.getBlock());
+                if (iblockdata.isComplexRedstone()) {
+                    this.updateAdjacentComparators(blockposition, newBlock.getBlock());
+                }
+            }
+
+            if ((i & 16) == 0) {
+                int j = i & -2;
+
+                // CraftBukkit start
+                iblockdata1.b(this, blockposition, j); // Don't call an event for the old block to limit event spam
+                CraftWorld world = ((WorldServer) this).getWorld();
+                if (world != null) {
+                    BlockPhysicsEvent event = new BlockPhysicsEvent(world.getBlockAt(blockposition.getX(), blockposition.getY(), blockposition.getZ()), CraftBlockData.fromData(iblockdata));
+                    this.getServer().getPluginManager().callEvent(event);
+
+                    if (event.isCancelled()) {
+                        return;
+                    }
+                }
+                // CraftBukkit end
+                iblockdata.a(this, blockposition, j);
+                iblockdata.b(this, blockposition, j);
+            }
+
+            this.a(blockposition, iblockdata1, iblockdata2);
+        }
+    }
+    // CraftBukkit end
+
     public void a(BlockPosition blockposition, IBlockData iblockdata, IBlockData iblockdata1) {}
 
     @Override
@@ -195,6 +345,11 @@
     @Override
     public void update(BlockPosition blockposition, Block block) {
         if (this.worldData.getType() != WorldType.DEBUG_ALL_BLOCK_STATES) {
+            // CraftBukkit start
+            if (populating) {
+                return;
+            }
+            // CraftBukkit end
             this.applyPhysics(blockposition, block);
         }
 
@@ -243,6 +398,17 @@
             IBlockData iblockdata = this.getType(blockposition);
 
             try {
+                // CraftBukkit start
+                CraftWorld world = ((WorldServer) this).getWorld();
+                if (world != null) {
+                    BlockPhysicsEvent event = new BlockPhysicsEvent(world.getBlockAt(blockposition.getX(), blockposition.getY(), blockposition.getZ()), CraftBlockData.fromData(iblockdata), world.getBlockAt(blockposition1.getX(), blockposition1.getY(), blockposition1.getZ()));
+                    this.getServer().getPluginManager().callEvent(event);
+
+                    if (event.isCancelled()) {
+                        return;
+                    }
+                }
+                // CraftBukkit end
                 iblockdata.doPhysics(this, blockposition, block, blockposition1, false);
             } catch (Throwable throwable) {
                 CrashReport crashreport = CrashReport.a(throwable, "Exception while updating neighbours");
@@ -285,6 +451,14 @@
 
     @Override
     public IBlockData getType(BlockPosition blockposition) {
+        // CraftBukkit start - tree generation
+        if (captureTreeGeneration) {
+            CapturedBlockState previous = capturedBlockStates.get(blockposition);
+            if (previous != null) {
+                return previous.getHandle();
+            }
+        }
+        // CraftBukkit end
         if (isOutsideWorld(blockposition)) {
             return Blocks.VOID_AIR.getBlockData();
         } else {
@@ -306,11 +480,11 @@
     }
 
     public boolean isDay() {
-        return this.worldProvider.getDimensionManager() == DimensionManager.OVERWORLD && this.c < 4;
+        return this.worldProvider.getDimensionManager().getType() == DimensionManager.OVERWORLD && this.c < 4; // CraftBukkit
     }
 
     public boolean isNight() {
-        return this.worldProvider.getDimensionManager() == DimensionManager.OVERWORLD && !this.isDay();
+        return this.worldProvider.getDimensionManager().getType() == DimensionManager.OVERWORLD && !this.isDay(); // CraftBukkit
     }
 
     @Override
@@ -432,9 +606,11 @@
                 TileEntity tileentity1 = (TileEntity) this.tileEntityListPending.get(i);
 
                 if (!tileentity1.isRemoved()) {
+                    /* CraftBukkit start - Order matters, moved down
                     if (!this.tileEntityList.contains(tileentity1)) {
                         this.a(tileentity1);
                     }
+                    // CraftBukkit end */
 
                     if (this.isLoaded(tileentity1.getPosition())) {
                         Chunk chunk = this.getChunkAtWorldCoords(tileentity1.getPosition());
@@ -442,6 +618,12 @@
 
                         chunk.setTileEntity(tileentity1.getPosition(), tileentity1);
                         this.notify(tileentity1.getPosition(), iblockdata, iblockdata, 3);
+                        // CraftBukkit start
+                        // From above, don't screw this up - SPIGOT-1746
+                        if (!this.tileEntityList.contains(tileentity1)) {
+                            this.a(tileentity1);
+                        }
+                        // CraftBukkit end
                     }
                 }
             }
@@ -606,12 +788,25 @@
 
     @Nullable
     @Override
+    // CraftBukkit start
     public TileEntity getTileEntity(BlockPosition blockposition) {
+        return getTileEntity(blockposition, true);
+    }
+
+    @Nullable
+    protected TileEntity getTileEntity(BlockPosition blockposition, boolean validate) {
+        // CraftBukkit end
         if (isOutsideWorld(blockposition)) {
             return null;
         } else if (!this.isClientSide && Thread.currentThread() != this.serverThread) {
             return null;
         } else {
+            // CraftBukkit start
+            if (capturedTileEntities.containsKey(blockposition)) {
+                return capturedTileEntities.get(blockposition);
+            }
+            // CraftBukkit end
+
             TileEntity tileentity = null;
 
             if (this.tickingTileEntities) {
@@ -646,6 +841,13 @@
     public void setTileEntity(BlockPosition blockposition, @Nullable TileEntity tileentity) {
         if (!isOutsideWorld(blockposition)) {
             if (tileentity != null && !tileentity.isRemoved()) {
+                // CraftBukkit start
+                if (captureBlockStates) {
+                    tileentity.setLocation(this, blockposition);
+                    capturedTileEntities.put(blockposition.immutableCopy(), tileentity);
+                    return;
+                }
+                // CraftBukkit end
                 if (this.tickingTileEntities) {
                     tileentity.setLocation(this, blockposition);
                     Iterator iterator = this.tileEntityListPending.iterator();
@@ -670,7 +872,7 @@
     }
 
     public void removeTileEntity(BlockPosition blockposition) {
-        TileEntity tileentity = this.getTileEntity(blockposition);
+        TileEntity tileentity = this.getTileEntity(blockposition, false); // CraftBukkit
 
         if (tileentity != null && this.tickingTileEntities) {
             tileentity.ab_();
