Java Thread - 如何组合putIfAbsent并替换为ConcurrentMap

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
class ReplaceWorker implements Runnable {
  public void run() {
    for (int i = 0; i < 100; i++) {
      Integer putIfAbsent = Main.map.putIfAbsent("key", Integer.valueOf(1));
      if (putIfAbsent == null)
        return;
      Main.map.replace("key", putIfAbsent + 1);
    }
  }
}
class MergeWorker implements Runnable {
  public void run() {
    for (int i = 0; i < 100; i++) {
      Main.map.merge("key", Integer.valueOf(1), (ov, nv) -> {
        return ov + 1;
      });
    }
  }
}

public class Main {
  static ConcurrentMap<String, Integer> map = new ConcurrentHashMap<>();
  public static void main(String[] args) {
    map.put("key", 1);
    Main test = new Main();
    ThreadPoolExecutor threadPool = new ThreadPoolExecutor(10, 10, 100,
        TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(1000));
    for (int i = 0; i < 100; i++) {
      threadPool.submit(new MergeWorker());
    }
    awaitTermination(threadPool);
    System.out.println(test.map.get("key"));

    map.put("key", 1);
    threadPool = new ThreadPoolExecutor(10, 10, 100, TimeUnit.MILLISECONDS,
        new ArrayBlockingQueue<>(1000));
    for (int i = 0; i < 100; i++) {
      threadPool.submit(new ReplaceWorker());
    }
    awaitTermination(threadPool);
    System.out.println(test.map.get("key"));
  }

  private static void awaitTermination(ExecutorService threadPool) {
    try {
      threadPool.shutdown();
      boolean awaitTermination = threadPool.awaitTermination(1,
          TimeUnit.SECONDS);
      System.out.println("terminted successfull: " + awaitTermination);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}