Problem. Creating a new world stops the server responses for some time

When I create a new world using WorldCreator, the server stops responding for at least 35 seconds and because of this, all the players on the server kick. And also, a thread dump is output to the console several times in a row, the last output contains information about the chunks of the generated world. If necessary, I will publish the log. My code:

Player player = (Player) sender;

World world = plugin.getServer().getWorld("KINGDOMS");
if (world == null) {
    WorldCreator wc = new WorldCreator("KINGDOMS");
    wc.environment(World.Environment.NORMAL);
    wc.type(WorldType.NORMAL);
    System.out.println("Starting generation of new world,");
    world = wc.createWorld();
    System.out.println("Generation ended.");
}
System.out.println("Teleportation");
player.teleport(world.getSpawnLocation());
System.out.println("Teleportation Ended");

player.sendTitle("Приветствую", "Добро пожаловать в королевства!", 3, 5000, 0);

return true;