List<World> worlds = new ArrayList<World>(queryCount);
Random random = ThreadLocalRandom.current();
for (int i = 0; i < queryCount; i++) {
World world = this.worldRepository.findOne(random.nextInt(DB_ROWS) + 1);
world.setRandomNumber(random.nextInt(DB_ROWS) + 1);
this.worldRepository.save(world);
worlds.add(world);
}
return worlds;