[Bug]NPE when unexport Metadata Services if the set of Metadata Service is null #6449
Description
- I have searched the issues of this repository and believe that this is not a duplicate.
- I have checked the FAQ of this repository and believe that this is not a duplicate.
Environment
- Dubbo version: 2.7.8-SNAPSHOT
- Operating System version: xxx
- Java version: xxx
Steps to reproduce this issue
- Do not start zookeeper server, which is used as a metadata center
- start a provider
Pls. provide [GitHub address] to reproduce this issue.
Expected Result
The app exit normally
Actual Result
The app exit with a NPE
If there is an exception, please attach the exception trace:
Exception in thread "DubboShutdownHook" java.lang.RuntimeException: java.lang.NullPointerException
at org.apache.dubbo.common.function.ThrowableAction.execute(ThrowableAction.java:48)
at org.apache.dubbo.common.lang.ShutdownHookCallbacks.lambda$callback$0(ShutdownHookCallbacks.java:70)
at java.base/java.lang.Iterable.forEach(Iterable.java:75)
at org.apache.dubbo.common.lang.ShutdownHookCallbacks.callback(ShutdownHookCallbacks.java:70)
at org.apache.dubbo.config.DubboShutdownHook.callback(DubboShutdownHook.java:85)
at org.apache.dubbo.config.DubboShutdownHook.run(DubboShutdownHook.java:73)
Caused by: java.lang.NullPointerException
at org.apache.dubbo.config.bootstrap.DubboBootstrap.unexportMetadataService(DubboBootstrap.java:1009)
at org.apache.dubbo.config.bootstrap.DubboBootstrap.destroy(DubboBootstrap.java:1188)
at org.apache.dubbo.config.bootstrap.DubboBootstrap$1.callback(DubboBootstrap.java:198)
at org.apache.dubbo.common.function.ThrowableAction.execute(ThrowableAction.java:46)
... 5 more