for (int i = 0; i < 100; i++) {
}
ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();
map.put("key1", 1);
map.put("key2", 2);
map.put("key3", 3);
AtomicInteger counter = new AtomicInteger(0);
new Thread(() -> {
}).start();
new Thread(() -> {
}).start();
