>cstest
[21:18:07] [Server thread/INFO]: [#getBlock#getBiome] Biome at (0, 15, 0): LUSH_CAVES
[21:18:07] [Server thread/INFO]: [#getBlock#getBiome] Biome at (0, 16, 0): OLD_GROWTH_PINE_TAIGA
[21:18:07] [Server thread/INFO]: [Snapshot#getBiome] Biome at (0, 15, 0): LUSH_CAVES
[21:18:07] [Server thread/WARN]: Unexpected exception while parsing console command "cstest"
org.bukkit.command.CommandException: Unhandled exception executing command 'cstest' in plugin ChunkSnapshotTest v0.0.1-SNAPSHOT
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[spigot-api-1.18-rc3-R0.1-SNAPSHOT.jar:?]
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:149) ~[spigot-api-1.18-rc3-R0.1-SNAPSHOT.jar:?]
    at org.bukkit.craftbukkit.v1_18_R1.CraftServer.dispatchCommand(CraftServer.java:800) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at org.bukkit.craftbukkit.v1_18_R1.CraftServer.dispatchServerCommand(CraftServer.java:785) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at net.minecraft.server.dedicated.DedicatedServer.bf(DedicatedServer.java:453) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at net.minecraft.server.dedicated.DedicatedServer.b(DedicatedServer.java:429) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:1205) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:1033) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at net.minecraft.server.MinecraftServer.lambda$0(MinecraftServer.java:303) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at java.lang.Thread.run(Thread.java:833) [?:?]
Caused by: java.lang.IllegalArgumentException: The value 64 is not in the specified inclusive range of 0 to 63
    at org.apache.commons.lang3.Validate.inclusiveBetween(Validate.java:1019) ~[commons-lang3-3.12.0.jar:3.12.0]
    at net.minecraft.util.SimpleBitStorage.a(SourceFile:184) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at net.minecraft.world.level.chunk.DataPaletteBlock.a(SourceFile:147) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at net.minecraft.world.level.chunk.DataPaletteBlock.a(SourceFile:141) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at org.bukkit.craftbukkit.v1_18_R1.CraftChunkSnapshot.getBiome(CraftChunkSnapshot.java:136) ~[spigot-1.18-rc3-R0.1-SNAPSHOT.jar:3323-Spigot-7514aa3-c86a3f7]
    at dev.ratas.cstest.ChunkSnapshotTest.onCommand(ChunkSnapshotTest.java:21) ~[?:?]
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[spigot-api-1.18-rc3-R0.1-SNAPSHOT.jar:?]
    ... 9 more  

package dev.ratas.cstest;

import org.bukkit.Chunk;
import org.bukkit.ChunkSnapshot;
import org.bukkit.World;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.plugin.java.JavaPlugin;

public class ChunkSnapshotTest extends JavaPlugin {

    @Override    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        World world = getServer().getWorld("world"); // default world
        Chunk chunk = world.getChunkAt(0, 0);
        ChunkSnapshot snapshot = chunk.getChunkSnapshot(false, true, false);
        sender.sendMessage("[#getBlock#getBiome] Biome at (0, 15, 0): " + chunk.getBlock(0, 15, 0).getBiome());
        sender.sendMessage("[#getBlock#getBiome] Biome at (0, 16, 0): " + chunk.getBlock(0, 16, 0).getBiome());
        sender.sendMessage("[Snapshot#getBiome] Biome at (0, 15, 0): " + snapshot.getBiome(0, 15, 0));
        sender.sendMessage("[Snapshot#getBiome] Biome at (0, 16, 0): " + snapshot.getBiome(0, 16, 0)); // Exception on this line!
        return true;
    }
}