- [ ] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.
- [ ] I have checked the [FAQ](https://github.com/apache/dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: xxx
* Operating System version: xxx
* Java version: xxx

### Steps to reproduce this issue

1. xxx
2. xxx
3. xxx

Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

What do you expected from the above steps？

### Actual Result

What actually happens?

If there is an exception, please attach the exception trace:

```
Just put your stack trace here!
```

/**
     * Get called when the server or client instance initiating.
     *
     * @param url
     * @return
     */
    public synchronized ExecutorService createExecutorIfAbsent(URL url) {
        Map<Integer, ExecutorService> executors = data.computeIfAbsent(EXECUTOR_SERVICE_COMPONENT_KEY, k -> new ConcurrentHashMap<>());
        
        Integer portKey = CONSUMER_SIDE.equalsIgnoreCase(url.getParameter(SIDE_KEY)) ? Integer.MAX_VALUE : url.getPort();
        ExecutorService executor = executors.computeIfAbsent(portKey, k -> createExecutor(url));
        
        if (executor.isShutdown() || executor.isTerminated()) {
            executors.remove(portKey);
            executor = createExecutor(url);
            executors.put(portKey, executor);
        }
        return executor;
    }
    public ExecutorService getExecutor(URL url) {
        Map<Integer, ExecutorService> executors = data.get(EXECUTOR_SERVICE_COMPONENT_KEY);
        /**
         * It's guaranteed that this method is called after {@link #createExecutorIfAbsent(URL)}, so data should already
         * have Executor instances generated and stored.
         */
        if (executors == null) {
            logger.warn("No available executors, this is not expected, framework should call createExecutorIfAbsent first " +
                    "before coming to here.");
            return null;
        }