Java starter bundle fails at Checkstyle

I tried running the original sample with `mvn spring-boot:run` but it fails at the Checkstyle step.

```
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 9.009 s
[INFO] Finished at: 2021-11-08T14:24:29+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:3.0.0:check (default) on project bundle-java: Failed during checkstyle execution: Failed during checkstyle configuration: unable to parse configuration stream: Connection refused: connect -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
```