defaultEventExecutorGroup在NettyClientBootstrap的start方法中被开启。

public void start() {
        if (this.defaultEventExecutorGroup == null) {
            this.defaultEventExecutorGroup = new DefaultEventExecutorGroup(nettyClientConfig.getClientWorkerThreads(),
                new NamedThreadFactory(getThreadPrefix(nettyClientConfig.getClientWorkerThreadPrefix()),
                    nettyClientConfig.getClientWorkerThreads()));
        }
        // ......
    }

根据它的命名NettyClientWorkerThread，它是一个worker线程组，但是我并没有发现使用到该线程组的地方。

String DEFAULT_SELECTOR_THREAD_PREFIX = "NettyClientSelector";
    String DEFAULT_WORKER_THREAD_PREFIX = "NettyClientWorkerThread";

这是不是意味着开启了一个占用系统资源但没什么用处的线程组？

defaultEventExecutorGroup is enabled in the startup method of NettyClientBootstrap.

public void start() {
        if (this.defaultEventExecutorGroup == null) {
            this.defaultEventExecutorGroup = new DefaultEventExecutorGroup(nettyClientConfig.getClientWorkerThreads(),
                new NamedThreadFactory(getThreadPrefix(nettyClientConfig.getClientWorkerThreadPrefix()),
                    nettyClientConfig.getClientWorkerThreads()));
        }
        // ......
    }

According to its naming NettyClientWorkerThread, it is a Worker thread group, but I didn't find any use for that thread group.

String DEFAULT_SELECTOR_THREAD_PREFIX = "NettyClientSelector";
    String DEFAULT_WORKER_THREAD_PREFIX = "NettyClientWorkerThread";

Does this mean that a thread group is opened that takes up system resources but is of little use?