首先，很明显，我对thenApply不太了解，这就是为什么我遇到编译器错误，但我尝试搜索但无法搜索。

这是我的简单代码：

import java.util.concurrent.CompletionStage;

public class Main5 {
    public static void main(String[] args) {

    }

    static class Game {
        public void doIt(int id) {
            CompletionStage<Player> player = getPlayer(id).thenApplyAsync(p -> {
                modifyPlayer(p.getId());
                return getPlayer(p.getId());
            });
        }

        private CompletionStage<Player> getPlayer(int id) {
            //do http request to get the player info
        }

        private CompletionStage<Void> modifyPlayer(int id) {
            //do http request to modify player's info
        }
    }
}

在thenApplySync中，我收到此编译器错误：

incompatible types: inference variable U has incompatible bounds
    equality constraints: com.testapp.Player
    lower bounds: java.util.concurrent.CompletionStage<com.testapp.Player>

getPlayer方法已经返回完成阶段，那怎么了？

我知道

感谢您的帮助。