server.java

///usr/bin/env jbang "$0" "$@" ; exit $?

//REPOS mavenCentral,sponge=https://repo.spongepowered.org/maven,jitpack=https://jitpack.io
//DEPS com.github.Minestom:Minestom:master-SNAPSHOT

import static java.lang.System.*;
import net.minestom.server.MinecraftServer;

public class server {

    public static void main(String[] args) {
        // Initialization
        MinecraftServer minecraftServer = MinecraftServer.init();
        InstanceManager instanceManager = MinecraftServer.getInstanceManager();
        // Create the instance
        InstanceContainer instanceContainer = instanceManager.createInstanceContainer();
        // Set the ChunkGenerator
        instanceContainer.setChunkGenerator(new GeneratorDemo());
        // Add an event callback to specify the spawning instance (and the spawn position)
        GlobalEventHandler globalEventHandler = MinecraftServer.getGlobalEventHandler();
        globalEventHandler.addListener(PlayerLoginEvent.class, event -> {
            final Player player = event.getPlayer();
            event.setSpawningInstance(instanceContainer);
            player.setRespawnPoint(new Pos(0, 42, 0));
        });
        // Start the server on port 25565
        minecraftServer.start("0.0.0.0", 25565);
    }
    private static class GeneratorDemo implements ChunkGenerator {
        @Override
        public void generateChunkData(ChunkBatch batch, int chunkX, int chunkZ) {
            // Set chunk blocks
            for (byte x = 0; x < Chunk.CHUNK_SIZE_X; x++) {
                for (byte z = 0; z < Chunk.CHUNK_SIZE_Z; z++) {
                    for (byte y = 0; y < 40; y++) {
                        batch.setBlock(x, y, z, Block.STONE);
                    }
                }
            }
        }
        @Override
        public void fillBiomes(Biome[] biomes, int chunkX, int chunkZ) {
            Arrays.fill(biomes, Biome.PLAINS);
        }
        @Override
        public List<ChunkPopulator> getPopulators() {
            return null;
        }
    }
}