--- a/net/minecraft/world/level/chunk/ChunkGenerator.java
+++ b/net/minecraft/world/level/chunk/ChunkGenerator.java
@@ -5,18 +5,19 @@
 import com.mojang.serialization.Codec;
 import com.mojang.serialization.MapCodec;
 import it.unimi.dsi.fastutil.ints.IntArraySet;
-import it.unimi.dsi.fastutil.ints.IntSet;
 import it.unimi.dsi.fastutil.longs.LongSet;
 import it.unimi.dsi.fastutil.objects.Object2ObjectArrayMap;
 import it.unimi.dsi.fastutil.objects.ObjectArraySet;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
-import java.util.Map.Entry;
 import java.util.concurrent.CompletableFuture;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -35,6 +36,7 @@
 import net.minecraft.core.Registry;
 import net.minecraft.core.RegistryAccess;
 import net.minecraft.core.SectionPos;
+import net.minecraft.core.Vec3i;
 import net.minecraft.core.registries.BuiltInRegistries;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.network.protocol.game.DebugPackets;
@@ -46,7 +48,6 @@
 import net.minecraft.world.level.ChunkPos;
 import net.minecraft.world.level.LevelHeightAccessor;
 import net.minecraft.world.level.LevelReader;
-import net.minecraft.world.level.NoiseColumn;
 import net.minecraft.world.level.StructureManager;
 import net.minecraft.world.level.WorldGenLevel;
 import net.minecraft.world.level.biome.Biome;
@@ -78,25 +79,26 @@
 import org.apache.commons.lang3.mutable.MutableBoolean;
 
 public abstract class ChunkGenerator {
-    public static final Codec<ChunkGenerator> CODEC = BuiltInRegistries.CHUNK_GENERATOR
-        .byNameCodec()
-        .dispatchStable(ChunkGenerator::codec, Function.identity());
+
+    public static final Codec<ChunkGenerator> CODEC = BuiltInRegistries.CHUNK_GENERATOR.byNameCodec().dispatchStable(ChunkGenerator::codec, Function.identity());
     protected final BiomeSource biomeSource;
     private final Supplier<List<FeatureSorter.StepFeatureData>> featuresPerStep;
     public final Function<Holder<Biome>, BiomeGenerationSettings> generationSettingsGetter;
 
     public ChunkGenerator(BiomeSource biomeSource) {
-        this(biomeSource, biomeEntry -> biomeEntry.value().getGenerationSettings());
+        this(biomeSource, (holder) -> {
+            return ((Biome) holder.value()).getGenerationSettings();
+        });
     }
 
     public ChunkGenerator(BiomeSource biomeSource, Function<Holder<Biome>, BiomeGenerationSettings> generationSettingsGetter) {
         this.biomeSource = biomeSource;
         this.generationSettingsGetter = generationSettingsGetter;
-        this.featuresPerStep = Suppliers.memoize(
-            () -> FeatureSorter.buildFeaturesPerStep(
-                    List.copyOf(biomeSource.possibleBiomes()), biomeEntry -> generationSettingsGetter.apply(biomeEntry).features(), true
-                )
-        );
+        this.featuresPerStep = Suppliers.memoize(() -> {
+            return FeatureSorter.buildFeaturesPerStep(List.copyOf(biomeSource.possibleBiomes()), (holder) -> {
+                return ((BiomeGenerationSettings) generationSettingsGetter.apply(holder)).features();
+            }, true);
+        });
     }
 
     public void validate() {
@@ -105,8 +107,8 @@
 
     protected abstract MapCodec<? extends ChunkGenerator> codec();
 
-    public ChunkGeneratorStructureState createState(HolderLookup<StructureSet> structureSetRegistry, RandomState noiseConfig, long seed) {
-        return ChunkGeneratorStructureState.createForNormal(noiseConfig, seed, this.biomeSource, structureSetRegistry);
+    public ChunkGeneratorStructureState createState(HolderLookup<StructureSet> holderlookup, RandomState randomstate, long i, org.spigotmc.SpigotWorldConfig conf) { // Spigot
+        return ChunkGeneratorStructureState.createForNormal(randomstate, i, this.biomeSource, holderlookup, conf); // Spigot
     }
 
     public Optional<ResourceKey<MapCodec<? extends ChunkGenerator>>> getTypeNameForDataFixer() {
@@ -117,29 +119,45 @@
         return CompletableFuture.supplyAsync(Util.wrapThreadWithTaskName("init_biomes", () -> {
             chunk.fillBiomesFromNoise(this.biomeSource, noiseConfig.sampler());
             return chunk;
-        }), Util.backgroundExecutor());
+        }), Runnable::run); // Paper - rewrite chunk system
     }
 
-    public abstract void applyCarvers(
-        WorldGenRegion chunkRegion,
-        long seed,
-        RandomState noiseConfig,
-        BiomeManager biomeAccess,
-        StructureManager structureAccessor,
-        ChunkAccess chunk,
-        GenerationStep.Carving carverStep
-    );
+    public abstract void applyCarvers(WorldGenRegion chunkRegion, long seed, RandomState noiseConfig, BiomeManager biomeAccess, StructureManager structureAccessor, ChunkAccess chunk, GenerationStep.Carving carverStep);
 
     @Nullable
-    public Pair<BlockPos, Holder<Structure>> findNearestMapStructure(
-        ServerLevel world, HolderSet<Structure> structures, BlockPos center, int radius, boolean skipReferencedStructures
-    ) {
-        ChunkGeneratorStructureState chunkGeneratorStructureState = world.getChunkSource().getGeneratorState();
-        Map<StructurePlacement, Set<Holder<Structure>>> map = new Object2ObjectArrayMap<>();
+    public Pair<BlockPos, Holder<Structure>> findNearestMapStructure(ServerLevel world, HolderSet<Structure> structures, BlockPos center, int radius, boolean skipReferencedStructures) {
+        // Paper start - StructuresLocateEvent
+        final org.bukkit.World bukkitWorld = world.getWorld();
+        final org.bukkit.Location origin = io.papermc.paper.util.MCUtil.toLocation(world, center);
+        final List<org.bukkit.generator.structure.Structure> apiStructures = structures.stream().map(Holder::value).map(nms -> org.bukkit.craftbukkit.generator.structure.CraftStructure.minecraftToBukkit(nms)).toList();
+        if (!apiStructures.isEmpty()) {
+            final io.papermc.paper.event.world.StructuresLocateEvent event = new io.papermc.paper.event.world.StructuresLocateEvent(bukkitWorld, origin, apiStructures, radius, skipReferencedStructures);
+            if (!event.callEvent()) {
+                return null;
+            }
+            if (event.getResult() != null) {
+                return Pair.of(io.papermc.paper.util.MCUtil.toBlockPos(event.getResult().pos()), world.registryAccess().registryOrThrow(Registries.STRUCTURE).wrapAsHolder(org.bukkit.craftbukkit.generator.structure.CraftStructure.bukkitToMinecraft(event.getResult().structure())));
+            }
+            center = io.papermc.paper.util.MCUtil.toBlockPosition(event.getOrigin());
+            radius = event.getRadius();
+            skipReferencedStructures = event.shouldFindUnexplored();
+            structures = HolderSet.direct(api -> world.registryAccess().registryOrThrow(Registries.STRUCTURE).wrapAsHolder(org.bukkit.craftbukkit.generator.structure.CraftStructure.bukkitToMinecraft(api)), event.getStructures());
+        }
+        // Paper end
+        ChunkGeneratorStructureState chunkgeneratorstructurestate = world.getChunkSource().getGeneratorState();
+        Map<StructurePlacement, Set<Holder<Structure>>> map = new Object2ObjectArrayMap();
+        Iterator iterator = structures.iterator();
 
-        for (Holder<Structure> holder : structures) {
-            for (StructurePlacement structurePlacement : chunkGeneratorStructureState.getPlacementsForStructure(holder)) {
-                map.computeIfAbsent(structurePlacement, placement -> new ObjectArraySet<>()).add(holder);
+        while (iterator.hasNext()) {
+            Holder<Structure> holder = (Holder) iterator.next();
+            Iterator iterator1 = chunkgeneratorstructurestate.getPlacementsForStructure(holder).iterator();
+
+            while (iterator1.hasNext()) {
+                StructurePlacement structureplacement = (StructurePlacement) iterator1.next();
+
+                ((Set) map.computeIfAbsent(structureplacement, (structureplacement1) -> {
+                    return new ObjectArraySet();
+                })).add(holder);
             }
         }
 
@@ -147,61 +165,58 @@
             return null;
         } else {
             Pair<BlockPos, Holder<Structure>> pair = null;
-            double d = Double.MAX_VALUE;
-            StructureManager structureManager = world.structureManager();
-            List<Entry<StructurePlacement, Set<Holder<Structure>>>> list = new ArrayList<>(map.size());
+            double d0 = Double.MAX_VALUE;
+            StructureManager structuremanager = world.structureManager();
+            List<Entry<StructurePlacement, Set<Holder<Structure>>>> list = new ArrayList(map.size());
+            Iterator iterator2 = map.entrySet().iterator();
 
-            for (Entry<StructurePlacement, Set<Holder<Structure>>> entry : map.entrySet()) {
-                StructurePlacement structurePlacement2 = entry.getKey();
-                if (structurePlacement2 instanceof ConcentricRingsStructurePlacement) {
-                    ConcentricRingsStructurePlacement concentricRingsStructurePlacement = (ConcentricRingsStructurePlacement)structurePlacement2;
-                    Pair<BlockPos, Holder<Structure>> pair2 = this.getNearestGeneratedStructure(
-                        entry.getValue(), world, structureManager, center, skipReferencedStructures, concentricRingsStructurePlacement
-                    );
-                    if (pair2 != null) {
-                        BlockPos blockPos = pair2.getFirst();
-                        double e = center.distSqr(blockPos);
-                        if (e < d) {
-                            d = e;
-                            pair = pair2;
+            while (iterator2.hasNext()) {
+                Entry<StructurePlacement, Set<Holder<Structure>>> entry = (Entry) iterator2.next();
+                StructurePlacement structureplacement1 = (StructurePlacement) entry.getKey();
+
+                if (structureplacement1 instanceof ConcentricRingsStructurePlacement) {
+                    ConcentricRingsStructurePlacement concentricringsstructureplacement = (ConcentricRingsStructurePlacement) structureplacement1;
+                    Pair<BlockPos, Holder<Structure>> pair1 = this.getNearestGeneratedStructure((Set) entry.getValue(), world, structuremanager, center, skipReferencedStructures, concentricringsstructureplacement);
+
+                    if (pair1 != null) {
+                        BlockPos blockposition1 = (BlockPos) pair1.getFirst();
+                        double d1 = center.distSqr(blockposition1);
+
+                        if (d1 < d0) {
+                            d0 = d1;
+                            pair = pair1;
                         }
                     }
-                } else if (structurePlacement2 instanceof RandomSpreadStructurePlacement) {
+                } else if (structureplacement1 instanceof RandomSpreadStructurePlacement) {
                     list.add(entry);
                 }
             }
 
             if (!list.isEmpty()) {
-                int i = SectionPos.blockToSectionCoord(center.getX());
-                int j = SectionPos.blockToSectionCoord(center.getZ());
+                int j = SectionPos.blockToSectionCoord(center.getX());
+                int k = SectionPos.blockToSectionCoord(center.getZ());
 
-                for (int k = 0; k <= radius; k++) {
-                    boolean bl = false;
+                for (int l = 0; l <= radius; ++l) {
+                    boolean flag1 = false;
+                    Iterator iterator3 = list.iterator();
 
-                    for (Entry<StructurePlacement, Set<Holder<Structure>>> entry2 : list) {
-                        RandomSpreadStructurePlacement randomSpreadStructurePlacement = (RandomSpreadStructurePlacement)entry2.getKey();
-                        Pair<BlockPos, Holder<Structure>> pair3 = getNearestGeneratedStructure(
-                            entry2.getValue(),
-                            world,
-                            structureManager,
-                            i,
-                            j,
-                            k,
-                            skipReferencedStructures,
-                            chunkGeneratorStructureState.getLevelSeed(),
-                            randomSpreadStructurePlacement
-                        );
-                        if (pair3 != null) {
-                            bl = true;
-                            double f = center.distSqr(pair3.getFirst());
-                            if (f < d) {
-                                d = f;
-                                pair = pair3;
+                    while (iterator3.hasNext()) {
+                        Entry<StructurePlacement, Set<Holder<Structure>>> entry1 = (Entry) iterator3.next();
+                        RandomSpreadStructurePlacement randomspreadstructureplacement = (RandomSpreadStructurePlacement) entry1.getKey();
+                        Pair<BlockPos, Holder<Structure>> pair2 = ChunkGenerator.getNearestGeneratedStructure((Set) entry1.getValue(), world, structuremanager, j, k, l, skipReferencedStructures, chunkgeneratorstructurestate.getLevelSeed(), randomspreadstructureplacement);
+
+                        if (pair2 != null) {
+                            flag1 = true;
+                            double d2 = center.distSqr((Vec3i) pair2.getFirst());
+
+                            if (d2 < d0) {
+                                d0 = d2;
+                                pair = pair2;
                             }
                         }
                     }
 
-                    if (bl) {
+                    if (flag1) {
                         return pair;
                     }
                 }
@@ -212,33 +227,31 @@
     }
 
     @Nullable
-    private Pair<BlockPos, Holder<Structure>> getNearestGeneratedStructure(
-        Set<Holder<Structure>> structures,
-        ServerLevel world,
-        StructureManager structureAccessor,
-        BlockPos center,
-        boolean skipReferencedStructures,
-        ConcentricRingsStructurePlacement placement
-    ) {
+    private Pair<BlockPos, Holder<Structure>> getNearestGeneratedStructure(Set<Holder<Structure>> structures, ServerLevel world, StructureManager structureAccessor, BlockPos center, boolean skipReferencedStructures, ConcentricRingsStructurePlacement placement) {
         List<ChunkPos> list = world.getChunkSource().getGeneratorState().getRingPositionsFor(placement);
+
         if (list == null) {
             throw new IllegalStateException("Somehow tried to find structures for a placement that doesn't exist");
         } else {
             Pair<BlockPos, Holder<Structure>> pair = null;
-            double d = Double.MAX_VALUE;
-            BlockPos.MutableBlockPos mutableBlockPos = new BlockPos.MutableBlockPos();
+            double d0 = Double.MAX_VALUE;
+            BlockPos.MutableBlockPos blockposition_mutableblockposition = new BlockPos.MutableBlockPos();
+            Iterator iterator = list.iterator();
 
-            for (ChunkPos chunkPos : list) {
-                mutableBlockPos.set(SectionPos.sectionToBlockCoord(chunkPos.x, 8), 32, SectionPos.sectionToBlockCoord(chunkPos.z, 8));
-                double e = mutableBlockPos.distSqr(center);
-                boolean bl = pair == null || e < d;
-                if (bl) {
-                    Pair<BlockPos, Holder<Structure>> pair2 = getStructureGeneratingAt(
-                        structures, world, structureAccessor, skipReferencedStructures, placement, chunkPos
-                    );
-                    if (pair2 != null) {
-                        pair = pair2;
-                        d = e;
+            while (iterator.hasNext()) {
+                ChunkPos chunkcoordintpair = (ChunkPos) iterator.next();
+                if (!world.paperConfig().environment.locateStructuresOutsideWorldBorder && !world.getWorldBorder().isChunkInBounds(chunkcoordintpair.x, chunkcoordintpair.z)) { continue; } // Paper - Bound treasure maps to world border
+
+                blockposition_mutableblockposition.set(SectionPos.sectionToBlockCoord(chunkcoordintpair.x, 8), 32, SectionPos.sectionToBlockCoord(chunkcoordintpair.z, 8));
+                double d1 = blockposition_mutableblockposition.distSqr(center);
+                boolean flag1 = pair == null || d1 < d0;
+
+                if (flag1) {
+                    Pair<BlockPos, Holder<Structure>> pair1 = ChunkGenerator.getStructureGeneratingAt(structures, world, structureAccessor, skipReferencedStructures, placement, chunkcoordintpair);
+
+                    if (pair1 != null) {
+                        pair = pair1;
+                        d0 = d1;
                     }
                 }
             }
@@ -248,31 +261,24 @@
     }
 
     @Nullable
-    private static Pair<BlockPos, Holder<Structure>> getNearestGeneratedStructure(
-        Set<Holder<Structure>> structures,
-        LevelReader world,
-        StructureManager structureAccessor,
-        int centerChunkX,
-        int centerChunkZ,
-        int radius,
-        boolean skipReferencedStructures,
-        long seed,
-        RandomSpreadStructurePlacement placement
-    ) {
-        int i = placement.spacing();
+    private static Pair<BlockPos, Holder<Structure>> getNearestGeneratedStructure(Set<Holder<Structure>> structures, LevelReader world, StructureManager structureAccessor, int centerChunkX, int centerChunkZ, int radius, boolean skipReferencedStructures, long seed, RandomSpreadStructurePlacement placement) {
+        int i1 = placement.spacing();
 
-        for (int j = -radius; j <= radius; j++) {
-            boolean bl = j == -radius || j == radius;
+        for (int j1 = -radius; j1 <= radius; ++j1) {
+            // Paper start - Perf: iterate over border chunks instead of entire square chunk area
+            boolean flag1 = j1 == -radius || j1 == radius; final boolean onBorderAlongZAxis = flag1; // Paper - OBFHELPER
+
+            for (int k1 = -radius; k1 <= radius; k1 += onBorderAlongZAxis ? 1 : radius * 2) {
+                // boolean flag2 = k1 == -radius || k1 == radius;
+
+                // if (flag1 || flag2) {
+                if (true) {
+                    // Paper end - Perf: iterate over border chunks instead of entire square chunk area
+                    int l1 = centerChunkX + i1 * j1;
+                    int i2 = centerChunkZ + i1 * k1;
+                    ChunkPos chunkcoordintpair = placement.getPotentialStructureChunk(seed, l1, i2);
+                    Pair<BlockPos, Holder<Structure>> pair = ChunkGenerator.getStructureGeneratingAt(structures, world, structureAccessor, skipReferencedStructures, placement, chunkcoordintpair);
 
-            for (int k = -radius; k <= radius; k++) {
-                boolean bl2 = k == -radius || k == radius;
-                if (bl || bl2) {
-                    int l = centerChunkX + i * j;
-                    int m = centerChunkZ + i * k;
-                    ChunkPos chunkPos = placement.getPotentialStructureChunk(seed, l, m);
-                    Pair<BlockPos, Holder<Structure>> pair = getStructureGeneratingAt(
-                        structures, world, structureAccessor, skipReferencedStructures, placement, chunkPos
-                    );
                     if (pair != null) {
                         return pair;
                     }
@@ -284,30 +290,38 @@
     }
 
     @Nullable
-    private static Pair<BlockPos, Holder<Structure>> getStructureGeneratingAt(
-        Set<Holder<Structure>> structures,
-        LevelReader world,
-        StructureManager structureAccessor,
-        boolean skipReferencedStructures,
-        StructurePlacement placement,
-        ChunkPos pos
-    ) {
-        for (Holder<Structure> holder : structures) {
-            StructureCheckResult structureCheckResult = structureAccessor.checkStructurePresence(pos, holder.value(), placement, skipReferencedStructures);
-            if (structureCheckResult != StructureCheckResult.START_NOT_PRESENT) {
-                if (!skipReferencedStructures && structureCheckResult == StructureCheckResult.START_PRESENT) {
-                    return Pair.of(placement.getLocatePos(pos), holder);
-                }
+    private static Pair<BlockPos, Holder<Structure>> getStructureGeneratingAt(Set<Holder<Structure>> structures, LevelReader world, StructureManager structureAccessor, boolean skipReferencedStructures, StructurePlacement placement, ChunkPos pos) {
+        Iterator iterator = structures.iterator();
 
-                ChunkAccess chunkAccess = world.getChunk(pos.x, pos.z, ChunkStatus.STRUCTURE_STARTS);
-                StructureStart structureStart = structureAccessor.getStartForStructure(SectionPos.bottomOf(chunkAccess), holder.value(), chunkAccess);
-                if (structureStart != null && structureStart.isValid() && (!skipReferencedStructures || tryAddReference(structureAccessor, structureStart))) {
-                    return Pair.of(placement.getLocatePos(structureStart.getChunkPos()), holder);
-                }
-            }
-        }
+        Holder holder;
+        StructureStart structurestart;
 
-        return null;
+        do {
+            do {
+                do {
+                    StructureCheckResult structurecheckresult;
+
+                    do {
+                        if (!iterator.hasNext()) {
+                            return null;
+                        }
+
+                        holder = (Holder) iterator.next();
+                        structurecheckresult = structureAccessor.checkStructurePresence(pos, (Structure) holder.value(), placement, skipReferencedStructures);
+                    } while (structurecheckresult == StructureCheckResult.START_NOT_PRESENT);
+
+                    if (!skipReferencedStructures && structurecheckresult == StructureCheckResult.START_PRESENT) {
+                        return Pair.of(placement.getLocatePos(pos), holder);
+                    }
+
+                    ChunkAccess ichunkaccess = ((ca.spottedleaf.moonrise.patches.chunk_system.level.ChunkSystemLevelReader)world).moonrise$syncLoadNonFull(pos.x, pos.z, ChunkStatus.STRUCTURE_STARTS); // Paper - rewrite chunk system
+
+                    structurestart = structureAccessor.getStartForStructure(SectionPos.bottomOf(ichunkaccess), (Structure) holder.value(), ichunkaccess);
+                } while (structurestart == null);
+            } while (!structurestart.isValid());
+        } while (skipReferencedStructures && !ChunkGenerator.tryAddReference(structureAccessor, structurestart));
+
+        return Pair.of(placement.getLocatePos(structurestart.getChunkPos()), holder);
     }
 
     private static boolean tryAddReference(StructureManager structureAccessor, StructureStart start) {
@@ -319,103 +333,181 @@
         }
     }
 
-    public void applyBiomeDecoration(WorldGenLevel world, ChunkAccess chunk, StructureManager structureAccessor) {
-        ChunkPos chunkPos = chunk.getPos();
-        if (!SharedConstants.debugVoidTerrain(chunkPos)) {
-            SectionPos sectionPos = SectionPos.of(chunkPos, world.getMinSection());
-            BlockPos blockPos = sectionPos.origin();
-            Registry<Structure> registry = world.registryAccess().registryOrThrow(Registries.STRUCTURE);
-            Map<Integer, List<Structure>> map = registry.stream().collect(Collectors.groupingBy(structureType -> structureType.step().ordinal()));
-            List<FeatureSorter.StepFeatureData> list = this.featuresPerStep.get();
-            WorldgenRandom worldgenRandom = new WorldgenRandom(new XoroshiroRandomSource(RandomSupport.generateUniqueSeed()));
-            long l = worldgenRandom.setDecorationSeed(world.getSeed(), blockPos.getX(), blockPos.getZ());
-            Set<Holder<Biome>> set = new ObjectArraySet<>();
-            ChunkPos.rangeClosed(sectionPos.chunk(), 1).forEach(pos -> {
-                ChunkAccess chunkAccess = world.getChunk(pos.x, pos.z);
+    public void addVanillaDecorations(WorldGenLevel generatoraccessseed, ChunkAccess ichunkaccess, StructureManager structuremanager) { // CraftBukkit
+        ChunkPos chunkcoordintpair = ichunkaccess.getPos();
 
-                for (LevelChunkSection levelChunkSection : chunkAccess.getSections()) {
-                    levelChunkSection.getBiomes().getAll(set::add);
+        if (!SharedConstants.debugVoidTerrain(chunkcoordintpair)) {
+            SectionPos sectionposition = SectionPos.of(chunkcoordintpair, generatoraccessseed.getMinSection());
+            BlockPos blockposition = sectionposition.origin();
+            Registry<Structure> iregistry = generatoraccessseed.registryAccess().registryOrThrow(Registries.STRUCTURE);
+            Map<Integer, List<Structure>> map = (Map) iregistry.stream().collect(Collectors.groupingBy((structure) -> {
+                return structure.step().ordinal();
+            }));
+            List<FeatureSorter.StepFeatureData> list = (List) this.featuresPerStep.get();
+            WorldgenRandom seededrandom = new WorldgenRandom(new XoroshiroRandomSource(RandomSupport.generateUniqueSeed()));
+            long i = seededrandom.setDecorationSeed(generatoraccessseed.getSeed(), blockposition.getX(), blockposition.getZ());
+            Set<Holder<Biome>> set = new ObjectArraySet();
+
+            ChunkPos.rangeClosed(sectionposition.chunk(), 1).forEach((chunkcoordintpair1) -> {
+                ChunkAccess ichunkaccess1 = generatoraccessseed.getChunk(chunkcoordintpair1.x, chunkcoordintpair1.z);
+                LevelChunkSection[] achunksection = ichunkaccess1.getSections();
+                int j = achunksection.length;
+
+                for (int k = 0; k < j; ++k) {
+                    LevelChunkSection chunksection = achunksection[k];
+                    PalettedContainerRO<Holder<Biome>> palettedcontainerro = chunksection.getBiomes(); // CraftBukkit - decompile error
+
+                    Objects.requireNonNull(set);
+                    palettedcontainerro.getAll(set::add);
                 }
+
             });
             set.retainAll(this.biomeSource.possibleBiomes());
-            int i = list.size();
+            int j = list.size();
 
             try {
-                Registry<PlacedFeature> registry2 = world.registryAccess().registryOrThrow(Registries.PLACED_FEATURE);
-                int j = Math.max(GenerationStep.Decoration.values().length, i);
+                Registry<PlacedFeature> iregistry1 = generatoraccessseed.registryAccess().registryOrThrow(Registries.PLACED_FEATURE);
+                int k = Math.max(GenerationStep.Decoration.values().length, j);
 
-                for (int k = 0; k < j; k++) {
-                    int m = 0;
-                    if (structureAccessor.shouldGenerateStructures()) {
-                        for (Structure structure : map.getOrDefault(k, Collections.emptyList())) {
-                            worldgenRandom.setFeatureSeed(l, m, k);
-                            Supplier<String> supplier = () -> registry.getResourceKey(structure).map(Object::toString).orElseGet(structure::toString);
+                for (int l = 0; l < k; ++l) {
+                    int i1 = 0;
+                    Iterator iterator;
+                    CrashReportCategory crashreportsystemdetails;
+
+                    if (structuremanager.shouldGenerateStructures()) {
+                        List<Structure> list1 = (List) map.getOrDefault(l, Collections.emptyList());
+
+                        for (iterator = list1.iterator(); iterator.hasNext(); ++i1) {
+                            Structure structure = (Structure) iterator.next();
+
+                            seededrandom.setFeatureSeed(i, i1, l);
+                            Supplier<String> supplier = () -> {
+                                Optional optional = iregistry.getResourceKey(structure).map(Object::toString);
+
+                                Objects.requireNonNull(structure);
+                                return (String) optional.orElseGet(structure::toString);
+                            };
 
                             try {
-                                world.setCurrentlyGenerating(supplier);
-                                structureAccessor.startsForStructure(sectionPos, structure)
-                                    .forEach(start -> start.placeInChunk(world, structureAccessor, this, worldgenRandom, getWritableArea(chunk), chunkPos));
-                            } catch (Exception var29) {
-                                CrashReport crashReport = CrashReport.forThrowable(var29, "Feature placement");
-                                crashReport.addCategory("Feature").setDetail("Description", supplier::get);
-                                throw new ReportedException(crashReport);
-                            }
+                                generatoraccessseed.setCurrentlyGenerating(supplier);
+                                structuremanager.startsForStructure(sectionposition, structure).forEach((structurestart) -> {
+                                    structurestart.placeInChunk(generatoraccessseed, structuremanager, this, seededrandom, ChunkGenerator.getWritableArea(ichunkaccess), chunkcoordintpair);
+                                });
+                            } catch (Exception exception) {
+                                CrashReport crashreport = CrashReport.forThrowable(exception, "Feature placement");
 
-                            m++;
+                                crashreportsystemdetails = crashreport.addCategory("Feature");
+                                Objects.requireNonNull(supplier);
+                                crashreportsystemdetails.setDetail("Description", supplier::get);
+                                throw new ReportedException(crashreport);
+                            }
                         }
                     }
 
-                    if (k < i) {
-                        IntSet intSet = new IntArraySet();
+                    if (l < j) {
+                        IntArraySet intarrayset = new IntArraySet();
 
-                        for (Holder<Biome> holder : set) {
-                            List<HolderSet<PlacedFeature>> list3 = this.generationSettingsGetter.apply(holder).features();
-                            if (k < list3.size()) {
-                                HolderSet<PlacedFeature> holderSet = list3.get(k);
-                                FeatureSorter.StepFeatureData stepFeatureData = list.get(k);
-                                holderSet.stream().map(Holder::value).forEach(feature -> intSet.add(stepFeatureData.indexMapping().applyAsInt(feature)));
+                        iterator = set.iterator();
+
+                        while (iterator.hasNext()) {
+                            Holder<Biome> holder = (Holder) iterator.next();
+                            List<HolderSet<PlacedFeature>> list2 = ((BiomeGenerationSettings) this.generationSettingsGetter.apply(holder)).features();
+
+                            if (l < list2.size()) {
+                                HolderSet<PlacedFeature> holderset = (HolderSet) list2.get(l);
+                                FeatureSorter.StepFeatureData featuresorter_b = (FeatureSorter.StepFeatureData) list.get(l);
+
+                                holderset.stream().map(Holder::value).forEach((placedfeature) -> {
+                                    intarrayset.add(featuresorter_b.indexMapping().applyAsInt(placedfeature));
+                                });
                             }
                         }
 
-                        int n = intSet.size();
-                        int[] is = intSet.toIntArray();
-                        Arrays.sort(is);
-                        FeatureSorter.StepFeatureData stepFeatureData2 = list.get(k);
+                        int j1 = intarrayset.size();
+                        int[] aint = intarrayset.toIntArray();
 
-                        for (int o = 0; o < n; o++) {
-                            int p = is[o];
-                            PlacedFeature placedFeature = stepFeatureData2.features().get(p);
-                            Supplier<String> supplier2 = () -> registry2.getResourceKey(placedFeature).map(Object::toString).orElseGet(placedFeature::toString);
-                            worldgenRandom.setFeatureSeed(l, p, k);
+                        Arrays.sort(aint);
+                        FeatureSorter.StepFeatureData featuresorter_b1 = (FeatureSorter.StepFeatureData) list.get(l);
+
+                        for (int k1 = 0; k1 < j1; ++k1) {
+                            int l1 = aint[k1];
+                            PlacedFeature placedfeature = (PlacedFeature) featuresorter_b1.features().get(l1);
+                            Supplier<String> supplier1 = () -> {
+                                Optional optional = iregistry1.getResourceKey(placedfeature).map(Object::toString);
+
+                                Objects.requireNonNull(placedfeature);
+                                return (String) optional.orElseGet(placedfeature::toString);
+                            };
+
+                            // Paper start - Configurable feature seeds; change populationSeed used in random
+                            long featurePopulationSeed = i;
+                            final long configFeatureSeed = generatoraccessseed.getMinecraftWorld().paperConfig().featureSeeds.features.getLong(placedfeature.feature());
+                            if (configFeatureSeed != -1) {
+                                featurePopulationSeed = seededrandom.setDecorationSeed(configFeatureSeed, blockposition.getX(), blockposition.getZ()); // See seededrandom.setDecorationSeed from above
+                            }
+                            seededrandom.setFeatureSeed(featurePopulationSeed, l1, l);
+                            // Paper end - Configurable feature seeds
 
                             try {
-                                world.setCurrentlyGenerating(supplier2);
-                                placedFeature.placeWithBiomeCheck(world, this, worldgenRandom, blockPos);
-                            } catch (Exception var30) {
-                                CrashReport crashReport2 = CrashReport.forThrowable(var30, "Feature placement");
-                                crashReport2.addCategory("Feature").setDetail("Description", supplier2::get);
-                                throw new ReportedException(crashReport2);
+                                generatoraccessseed.setCurrentlyGenerating(supplier1);
+                                placedfeature.placeWithBiomeCheck(generatoraccessseed, this, seededrandom, blockposition);
+                            } catch (Exception exception1) {
+                                CrashReport crashreport1 = CrashReport.forThrowable(exception1, "Feature placement");
+
+                                crashreportsystemdetails = crashreport1.addCategory("Feature");
+                                Objects.requireNonNull(supplier1);
+                                crashreportsystemdetails.setDetail("Description", supplier1::get);
+                                throw new ReportedException(crashreport1);
                             }
                         }
                     }
                 }
 
-                world.setCurrentlyGenerating(null);
-            } catch (Exception var31) {
-                CrashReport crashReport3 = CrashReport.forThrowable(var31, "Biome decoration");
-                crashReport3.addCategory("Generation").setDetail("CenterX", chunkPos.x).setDetail("CenterZ", chunkPos.z).setDetail("Decoration Seed", l);
-                throw new ReportedException(crashReport3);
+                generatoraccessseed.setCurrentlyGenerating((Supplier) null);
+            } catch (Exception exception2) {
+                CrashReport crashreport2 = CrashReport.forThrowable(exception2, "Biome decoration");
+
+                crashreport2.addCategory("Generation").setDetail("CenterX", (Object) chunkcoordintpair.x).setDetail("CenterZ", (Object) chunkcoordintpair.z).setDetail("Decoration Seed", (Object) i);
+                throw new ReportedException(crashreport2);
+            }
+        }
+    }
+
+   // CraftBukkit start
+    public void applyBiomeDecoration(WorldGenLevel world, ChunkAccess chunk, StructureManager structureAccessor) {
+        this.applyBiomeDecoration(world, chunk, structureAccessor, true);
+    }
+
+    public void applyBiomeDecoration(WorldGenLevel generatoraccessseed, ChunkAccess ichunkaccess, StructureManager structuremanager, boolean vanilla) {
+        if (vanilla) {
+            this.addVanillaDecorations(generatoraccessseed, ichunkaccess, structuremanager);
+        }
+
+        org.bukkit.World world = generatoraccessseed.getMinecraftWorld().getWorld();
+        // only call when a populator is present (prevents unnecessary entity conversion)
+        if (!world.getPopulators().isEmpty()) {
+            org.bukkit.craftbukkit.generator.CraftLimitedRegion limitedRegion = new org.bukkit.craftbukkit.generator.CraftLimitedRegion(generatoraccessseed, ichunkaccess.getPos());
+            int x = ichunkaccess.getPos().x;
+            int z = ichunkaccess.getPos().z;
+            for (org.bukkit.generator.BlockPopulator populator : world.getPopulators()) {
+                WorldgenRandom seededrandom = new WorldgenRandom(new net.minecraft.world.level.levelgen.LegacyRandomSource(generatoraccessseed.getSeed()));
+                seededrandom.setDecorationSeed(generatoraccessseed.getSeed(), x, z);
+                populator.populate(world, new org.bukkit.craftbukkit.util.RandomSourceWrapper.RandomWrapper(seededrandom), x, z, limitedRegion);
             }
+            limitedRegion.saveEntities();
+            limitedRegion.breakLink();
         }
     }
+    // CraftBukkit end
 
     private static BoundingBox getWritableArea(ChunkAccess chunk) {
-        ChunkPos chunkPos = chunk.getPos();
-        int i = chunkPos.getMinBlockX();
-        int j = chunkPos.getMinBlockZ();
-        LevelHeightAccessor levelHeightAccessor = chunk.getHeightAccessorForGeneration();
-        int k = levelHeightAccessor.getMinBuildHeight() + 1;
-        int l = levelHeightAccessor.getMaxBuildHeight() - 1;
+        ChunkPos chunkcoordintpair = chunk.getPos();
+        int i = chunkcoordintpair.getMinBlockX();
+        int j = chunkcoordintpair.getMinBlockZ();
+        LevelHeightAccessor levelheightaccessor = chunk.getHeightAccessorForGeneration();
+        int k = levelheightaccessor.getMinBuildHeight() + 1;
+        int l = levelheightaccessor.getMaxBuildHeight() - 1;
+
         return new BoundingBox(i, k, j, i + 15, l, j + 15);
     }
 
@@ -435,133 +527,125 @@
 
     public WeightedRandomList<MobSpawnSettings.SpawnerData> getMobsAt(Holder<Biome> biome, StructureManager accessor, MobCategory group, BlockPos pos) {
         Map<Structure, LongSet> map = accessor.getAllStructuresAt(pos);
+        Iterator iterator = map.entrySet().iterator();
 
-        for (Entry<Structure, LongSet> entry : map.entrySet()) {
-            Structure structure = entry.getKey();
-            StructureSpawnOverride structureSpawnOverride = structure.spawnOverrides().get(group);
-            if (structureSpawnOverride != null) {
-                MutableBoolean mutableBoolean = new MutableBoolean(false);
-                Predicate<StructureStart> predicate = structureSpawnOverride.boundingBox() == StructureSpawnOverride.BoundingBoxType.PIECE
-                    ? start -> accessor.structureHasPieceAt(pos, start)
-                    : start -> start.getBoundingBox().isInside(pos);
-                accessor.fillStartsForStructure(structure, entry.getValue(), start -> {
-                    if (mutableBoolean.isFalse() && predicate.test(start)) {
-                        mutableBoolean.setTrue();
+        while (iterator.hasNext()) {
+            Entry<Structure, LongSet> entry = (Entry) iterator.next();
+            Structure structure = (Structure) entry.getKey();
+            StructureSpawnOverride structurespawnoverride = (StructureSpawnOverride) structure.spawnOverrides().get(group);
+
+            if (structurespawnoverride != null) {
+                MutableBoolean mutableboolean = new MutableBoolean(false);
+                Predicate<StructureStart> predicate = structurespawnoverride.boundingBox() == StructureSpawnOverride.BoundingBoxType.PIECE ? (structurestart) -> {
+                    return accessor.structureHasPieceAt(pos, structurestart);
+                } : (structurestart) -> {
+                    return structurestart.getBoundingBox().isInside(pos);
+                };
+
+                accessor.fillStartsForStructure(structure, (LongSet) entry.getValue(), (structurestart) -> {
+                    if (mutableboolean.isFalse() && predicate.test(structurestart)) {
+                        mutableboolean.setTrue();
                     }
+
                 });
-                if (mutableBoolean.isTrue()) {
-                    return structureSpawnOverride.spawns();
+                if (mutableboolean.isTrue()) {
+                    return structurespawnoverride.spawns();
                 }
             }
         }
 
-        return biome.value().getMobSettings().getMobs(group);
+        return ((Biome) biome.value()).getMobSettings().getMobs(group);
     }
 
-    public void createStructures(
-        RegistryAccess registryManager,
-        ChunkGeneratorStructureState placementCalculator,
-        StructureManager structureAccessor,
-        ChunkAccess chunk,
-        StructureTemplateManager structureTemplateManager
-    ) {
-        ChunkPos chunkPos = chunk.getPos();
-        SectionPos sectionPos = SectionPos.bottomOf(chunk);
-        RandomState randomState = placementCalculator.randomState();
-        placementCalculator.possibleStructureSets()
-            .forEach(
-                structureSet -> {
-                    StructurePlacement structurePlacement = structureSet.value().placement();
-                    List<StructureSet.StructureSelectionEntry> list = structureSet.value().structures();
+    public void createStructures(RegistryAccess registryManager, ChunkGeneratorStructureState placementCalculator, StructureManager structureAccessor, ChunkAccess chunk, StructureTemplateManager structureTemplateManager) {
+        ChunkPos chunkcoordintpair = chunk.getPos();
+        SectionPos sectionposition = SectionPos.bottomOf(chunk);
+        RandomState randomstate = placementCalculator.randomState();
 
-                    for (StructureSet.StructureSelectionEntry structureSelectionEntry : list) {
-                        StructureStart structureStart = structureAccessor.getStartForStructure(sectionPos, structureSelectionEntry.structure().value(), chunk);
-                        if (structureStart != null && structureStart.isValid()) {
-                            return;
-                        }
-                    }
+        placementCalculator.possibleStructureSets().forEach((holder) -> {
+            StructurePlacement structureplacement = ((StructureSet) holder.value()).placement();
+            List<StructureSet.StructureSelectionEntry> list = ((StructureSet) holder.value()).structures();
+            Iterator iterator = list.iterator();
 
-                    if (structurePlacement.isStructureChunk(placementCalculator, chunkPos.x, chunkPos.z)) {
-                        if (list.size() == 1) {
-                            this.tryGenerateStructure(
-                                list.get(0),
-                                structureAccessor,
-                                registryManager,
-                                randomState,
-                                structureTemplateManager,
-                                placementCalculator.getLevelSeed(),
-                                chunk,
-                                chunkPos,
-                                sectionPos
-                            );
-                        } else {
-                            ArrayList<StructureSet.StructureSelectionEntry> arrayList = new ArrayList<>(list.size());
-                            arrayList.addAll(list);
-                            WorldgenRandom worldgenRandom = new WorldgenRandom(new LegacyRandomSource(0L));
-                            worldgenRandom.setLargeFeatureSeed(placementCalculator.getLevelSeed(), chunkPos.x, chunkPos.z);
-                            int i = 0;
+            while (iterator.hasNext()) {
+                StructureSet.StructureSelectionEntry structureset_a = (StructureSet.StructureSelectionEntry) iterator.next();
+                StructureStart structurestart = structureAccessor.getStartForStructure(sectionposition, (Structure) structureset_a.structure().value(), chunk);
 
-                            for (StructureSet.StructureSelectionEntry structureSelectionEntry2 : arrayList) {
-                                i += structureSelectionEntry2.weight();
-                            }
+                if (structurestart != null && structurestart.isValid()) {
+                    return;
+                }
+            }
 
-                            while (!arrayList.isEmpty()) {
-                                int j = worldgenRandom.nextInt(i);
-                                int k = 0;
+            if (structureplacement.isStructureChunk(placementCalculator, chunkcoordintpair.x, chunkcoordintpair.z, structureplacement instanceof net.minecraft.world.level.chunk.ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement keyed ? keyed.key : null)) { // Paper - Add missing structure set seed configs
+                if (list.size() == 1) {
+                    this.tryGenerateStructure((StructureSet.StructureSelectionEntry) list.get(0), structureAccessor, registryManager, randomstate, structureTemplateManager, placementCalculator.getLevelSeed(), chunk, chunkcoordintpair, sectionposition);
+                } else {
+                    ArrayList<StructureSet.StructureSelectionEntry> arraylist = new ArrayList(list.size());
 
-                                for (StructureSet.StructureSelectionEntry structureSelectionEntry3 : arrayList) {
-                                    j -= structureSelectionEntry3.weight();
-                                    if (j < 0) {
-                                        break;
-                                    }
+                    arraylist.addAll(list);
+                    WorldgenRandom seededrandom = new WorldgenRandom(new LegacyRandomSource(0L));
 
-                                    k++;
-                                }
+                    seededrandom.setLargeFeatureSeed(placementCalculator.getLevelSeed(), chunkcoordintpair.x, chunkcoordintpair.z);
+                    int i = 0;
 
-                                StructureSet.StructureSelectionEntry structureSelectionEntry4 = arrayList.get(k);
-                                if (this.tryGenerateStructure(
-                                    structureSelectionEntry4,
-                                    structureAccessor,
-                                    registryManager,
-                                    randomState,
-                                    structureTemplateManager,
-                                    placementCalculator.getLevelSeed(),
-                                    chunk,
-                                    chunkPos,
-                                    sectionPos
-                                )) {
-                                    return;
+                    StructureSet.StructureSelectionEntry structureset_a1;
+
+                    for (Iterator iterator1 = arraylist.iterator(); iterator1.hasNext(); i += structureset_a1.weight()) {
+                        structureset_a1 = (StructureSet.StructureSelectionEntry) iterator1.next();
+                    }
+
+                    while (!arraylist.isEmpty()) {
+                        int j = seededrandom.nextInt(i);
+                        int k = 0;
+                        Iterator iterator2 = arraylist.iterator();
+
+                        while (true) {
+                            if (iterator2.hasNext()) {
+                                StructureSet.StructureSelectionEntry structureset_a2 = (StructureSet.StructureSelectionEntry) iterator2.next();
+
+                                j -= structureset_a2.weight();
+                                if (j >= 0) {
+                                    ++k;
+                                    continue;
                                 }
+                            }
 
-                                arrayList.remove(k);
-                                i -= structureSelectionEntry4.weight();
+                            StructureSet.StructureSelectionEntry structureset_a3 = (StructureSet.StructureSelectionEntry) arraylist.get(k);
+
+                            if (this.tryGenerateStructure(structureset_a3, structureAccessor, registryManager, randomstate, structureTemplateManager, placementCalculator.getLevelSeed(), chunk, chunkcoordintpair, sectionposition)) {
+                                return;
                             }
+
+                            arraylist.remove(k);
+                            i -= structureset_a3.weight();
+                            break;
                         }
                     }
+
                 }
-            );
+            }
+        });
     }
 
-    private boolean tryGenerateStructure(
-        StructureSet.StructureSelectionEntry weightedEntry,
-        StructureManager structureAccessor,
-        RegistryAccess dynamicRegistryManager,
-        RandomState noiseConfig,
-        StructureTemplateManager structureManager,
-        long seed,
-        ChunkAccess chunk,
-        ChunkPos pos,
-        SectionPos sectionPos
-    ) {
-        Structure structure = weightedEntry.structure().value();
-        int i = fetchReferences(structureAccessor, chunk, sectionPos, structure);
-        HolderSet<Biome> holderSet = structure.biomes();
-        Predicate<Holder<Biome>> predicate = holderSet::contains;
-        StructureStart structureStart = structure.generate(
-            dynamicRegistryManager, this, this.biomeSource, noiseConfig, structureManager, seed, pos, i, chunk, predicate
-        );
-        if (structureStart.isValid()) {
-            structureAccessor.setStartForStructure(sectionPos, structure, structureStart, chunk);
+    private boolean tryGenerateStructure(StructureSet.StructureSelectionEntry weightedEntry, StructureManager structureAccessor, RegistryAccess dynamicRegistryManager, RandomState noiseConfig, StructureTemplateManager structureManager, long seed, ChunkAccess chunk, ChunkPos pos, SectionPos sectionPos) {
+        Structure structure = (Structure) weightedEntry.structure().value();
+        int j = ChunkGenerator.fetchReferences(structureAccessor, chunk, sectionPos, structure);
+        HolderSet<Biome> holderset = structure.biomes();
+
+        Objects.requireNonNull(holderset);
+        Predicate<Holder<Biome>> predicate = holderset::contains;
+        StructureStart structurestart = structure.generate(dynamicRegistryManager, this, this.biomeSource, noiseConfig, structureManager, seed, pos, j, chunk, predicate);
+
+        if (structurestart.isValid()) {
+            // CraftBukkit start
+            BoundingBox box = structurestart.getBoundingBox();
+            org.bukkit.event.world.AsyncStructureSpawnEvent event = new org.bukkit.event.world.AsyncStructureSpawnEvent(structureAccessor.level.getMinecraftWorld().getWorld(), org.bukkit.craftbukkit.generator.structure.CraftStructure.minecraftToBukkit(structure), new org.bukkit.util.BoundingBox(box.minX(), box.minY(), box.minZ(), box.maxX(), box.maxY(), box.maxZ()), pos.x, pos.z);
+            org.bukkit.Bukkit.getPluginManager().callEvent(event);
+            if (event.isCancelled()) {
+                return true;
+            }
+            // CraftBukkit end
+            structureAccessor.setStartForStructure(sectionPos, structure, structurestart, chunk);
             return true;
         } else {
             return false;
@@ -569,50 +653,58 @@
     }
 
     private static int fetchReferences(StructureManager structureAccessor, ChunkAccess chunk, SectionPos sectionPos, Structure structure) {
-        StructureStart structureStart = structureAccessor.getStartForStructure(sectionPos, structure, chunk);
-        return structureStart != null ? structureStart.getReferences() : 0;
+        StructureStart structurestart = structureAccessor.getStartForStructure(sectionPos, structure, chunk);
+
+        return structurestart != null ? structurestart.getReferences() : 0;
     }
 
     public void createReferences(WorldGenLevel world, StructureManager structureAccessor, ChunkAccess chunk) {
-        int i = 8;
-        ChunkPos chunkPos = chunk.getPos();
-        int j = chunkPos.x;
-        int k = chunkPos.z;
-        int l = chunkPos.getMinBlockX();
-        int m = chunkPos.getMinBlockZ();
-        SectionPos sectionPos = SectionPos.bottomOf(chunk);
+        boolean flag = true;
+        ChunkPos chunkcoordintpair = chunk.getPos();
+        int i = chunkcoordintpair.x;
+        int j = chunkcoordintpair.z;
+        int k = chunkcoordintpair.getMinBlockX();
+        int l = chunkcoordintpair.getMinBlockZ();
+        SectionPos sectionposition = SectionPos.bottomOf(chunk);
 
-        for (int n = j - 8; n <= j + 8; n++) {
-            for (int o = k - 8; o <= k + 8; o++) {
-                long p = ChunkPos.asLong(n, o);
+        for (int i1 = i - 8; i1 <= i + 8; ++i1) {
+            for (int j1 = j - 8; j1 <= j + 8; ++j1) {
+                long k1 = ChunkPos.asLong(i1, j1);
+                Iterator iterator = world.getChunk(i1, j1).getAllStarts().values().iterator();
+
+                while (iterator.hasNext()) {
+                    StructureStart structurestart = (StructureStart) iterator.next();
 
-                for (StructureStart structureStart : world.getChunk(n, o).getAllStarts().values()) {
                     try {
-                        if (structureStart.isValid() && structureStart.getBoundingBox().intersects(l, m, l + 15, m + 15)) {
-                            structureAccessor.addReferenceForStructure(sectionPos, structureStart.getStructure(), p, chunk);
-                            DebugPackets.sendStructurePacket(world, structureStart);
+                        if (structurestart.isValid() && structurestart.getBoundingBox().intersects(k, l, k + 15, l + 15)) {
+                            structureAccessor.addReferenceForStructure(sectionposition, structurestart.getStructure(), k1, chunk);
+                            DebugPackets.sendStructurePacket(world, structurestart);
                         }
-                    } catch (Exception var21) {
-                        CrashReport crashReport = CrashReport.forThrowable(var21, "Generating structure reference");
-                        CrashReportCategory crashReportCategory = crashReport.addCategory("Structure");
+                    } catch (Exception exception) {
+                        CrashReport crashreport = CrashReport.forThrowable(exception, "Generating structure reference");
+                        CrashReportCategory crashreportsystemdetails = crashreport.addCategory("Structure");
                         Optional<? extends Registry<Structure>> optional = world.registryAccess().registry(Registries.STRUCTURE);
-                        crashReportCategory.setDetail(
-                            "Id",
-                            () -> optional.<String>map(structureTypeRegistry -> structureTypeRegistry.getKey(structureStart.getStructure()).toString())
-                                    .orElse("UNKNOWN")
-                        );
-                        crashReportCategory.setDetail("Name", () -> BuiltInRegistries.STRUCTURE_TYPE.getKey(structureStart.getStructure().type()).toString());
-                        crashReportCategory.setDetail("Class", () -> structureStart.getStructure().getClass().getCanonicalName());
-                        throw new ReportedException(crashReport);
+
+                        crashreportsystemdetails.setDetail("Id", () -> {
+                            return (String) optional.map((iregistry) -> {
+                                return iregistry.getKey(structurestart.getStructure()).toString();
+                            }).orElse("UNKNOWN");
+                        });
+                        crashreportsystemdetails.setDetail("Name", () -> {
+                            return BuiltInRegistries.STRUCTURE_TYPE.getKey(structurestart.getStructure().type()).toString();
+                        });
+                        crashreportsystemdetails.setDetail("Class", () -> {
+                            return structurestart.getStructure().getClass().getCanonicalName();
+                        });
+                        throw new ReportedException(crashreport);
                     }
                 }
             }
         }
+
     }
 
-    public abstract CompletableFuture<ChunkAccess> fillFromNoise(
-        Blender blender, RandomState noiseConfig, StructureManager structureAccessor, ChunkAccess chunk
-    );
+    public abstract CompletableFuture<ChunkAccess> fillFromNoise(Blender blender, RandomState noiseConfig, StructureManager structureAccessor, ChunkAccess chunk);
 
     public abstract int getSeaLevel();
 
@@ -620,7 +712,7 @@
 
     public abstract int getBaseHeight(int x, int z, Heightmap.Types heightmap, LevelHeightAccessor world, RandomState noiseConfig);
 
-    public abstract NoiseColumn getBaseColumn(int x, int z, LevelHeightAccessor world, RandomState noiseConfig);
+    public abstract net.minecraft.world.level.NoiseColumn getBaseColumn(int x, int z, LevelHeightAccessor world, RandomState noiseConfig);
 
     public int getFirstFreeHeight(int x, int z, Heightmap.Types heightmap, LevelHeightAccessor world, RandomState noiseConfig) {
         return this.getBaseHeight(x, z, heightmap, world, noiseConfig);
@@ -632,8 +724,9 @@
 
     public abstract void addDebugScreenInfo(List<String> text, RandomState noiseConfig, BlockPos pos);
 
+    /** @deprecated */
     @Deprecated
     public BiomeGenerationSettings getBiomeGenerationSettings(Holder<Biome> biomeEntry) {
-        return this.generationSettingsGetter.apply(biomeEntry);
+        return (BiomeGenerationSettings) this.generationSettingsGetter.apply(biomeEntry);
     }
 }
