- [ ] 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!
```

@Override
    public void doUnsubscribe(URL url, NotifyListener listener) {
        if (isAdminProtocol(url)) {
            shutdownServiceNamesLookup();
        }
    }
    private void shutdownServiceNamesLookup() {
        if (scheduledExecutorService != null) {
            scheduledExecutorService.shutdown();
        }
    }
    /**
     * Get the service names from the specified {@link URL url}
     *
     * @param url      {@link URL}
     * @param listener {@link NotifyListener}
     * @return non-null
     */
    private Set<String> getServiceNames(URL url, NotifyListener listener) {
        if (isAdminProtocol(url)) {
            scheduleServiceNamesLookup(url, listener);
            return getServiceNamesForOps(url);
        } else {
            return getServiceNames0(url);
        }
    }
    private Set<String> getServiceNames0(URL url) {
        NacosServiceName serviceName = createServiceName(url);
        final Set<String> serviceNames;
        if (serviceName.isConcrete()) {