Minestom/src/main/java/fr/themode/demo/MainDemo.java

package fr.themode.demo;

import net.minestom.server.MinecraftServer;
import net.minestom.server.event.player.PlayerLoginEvent;
import net.minestom.server.event.player.PlayerSpawnEvent;
import net.minestom.server.instance.*;
import net.minestom.server.instance.batch.ChunkBatch;
import net.minestom.server.instance.block.Block;
import net.minestom.server.network.ConnectionManager;
import net.minestom.server.utils.Position;

import java.util.Arrays;
import java.util.List;

public class MainDemo {

    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());
        // Enable the auto chunk loading (when players come close)
        instanceContainer.enableAutoChunkLoad(true);

        // Add event listeners
        ConnectionManager connectionManager = MinecraftServer.getConnectionManager();
        connectionManager.addPlayerInitialization(player -> {
            // Set the spawning instance
            player.addEventCallback(PlayerLoginEvent.class, event -> {
                event.setSpawningInstance(instanceContainer);
            });

            // Teleport the player at spawn
            player.addEventCallback(PlayerSpawnEvent.class, event -> {
                player.teleport(new Position(0, 45, 0));
            });
        });

        // Start the server
        minecraftServer.start("localhost", 55555);
    }

    private static class GeneratorDemo extends 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;
        }
    }

}