Issue 1:
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: xxx

Operating System version: xxx

Java version: xxx

Steps to reproduce this issue

xxx

xxx

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!

Dubbo USES redis as the registry times error below:

Exception in thread "main" java.lang.IllegalStateException: No such extension org.apache.dubbo.registry.RegistryFactory by name dubbo

at org.apache.dubbo.common.extension.ExtensionLoader.findException(ExtensionLoader.java:499)

at org.apache.dubbo.common.extension.ExtensionLoader.createExtension(ExtensionLoader.java:506)

at org.apache.dubbo.common.extension.ExtensionLoader.getExtension(ExtensionLoader.java:325)

at org.apache.dubbo.registry.RegistryFactory$Adaptive.getRegistry(RegistryFactory$Adaptive.java)

at org.apache.dubbo.registry.integration.RegistryProtocol.getRegistry(RegistryProtocol.java:204)

at org.apache.dubbo.registry.integration.RegistryProtocol.export(RegistryProtocol.java:138)

at org.apache.dubbo.rpc.protocol.ProtocolListenerWrapper.export(ProtocolListenerWrapper.java:55)

at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper.export(ProtocolFilterWrapper.java:98)

at org.apache.dubbo.rpc.Protocol$Adaptive.export(Protocol$Adaptive.java)

at org.apache.dubbo.config.ServiceConfig.doExportUrlsFor1Protocol(ServiceConfig.java:512)

at org.apache.dubbo.config.ServiceConfig.doExportUrls(ServiceConfig.java:357)

at org.apache.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:316)

at org.apache.dubbo.config.ServiceConfig.export(ServiceConfig.java:215)

at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:114)

at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:49)

at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)

at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)

at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)

at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:393)

at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:347)

at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:883)

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)

at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:139)

at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:93)

at org.apache.dubbo.demo.provider.Provider.main(Provider.java:29)

[02/11/18 06:53:02:002 CST] main WARN extension.ExtensionLoader: [DUBBO] Failed to find extension named redis for type org.apache.dubbo.registry.RegistryFactory, will use default extension dubbo instead., dubbo version: , current host: 192.168.0.142

java.lang.IllegalStateException: No such extension org.apache.dubbo.registry.RegistryFactory by name redis

at org.apache.dubbo.common.extension.ExtensionLoader.findException(ExtensionLoader.java:499)

at org.apache.dubbo.common.extension.ExtensionLoader.createExtension(ExtensionLoader.java:506)

at org.apache.dubbo.common.extension.ExtensionLoader.getExtension(ExtensionLoader.java:325)

at org.apache.dubbo.registry.RegistryFactory$Adaptive.getRegistry(RegistryFactory$Adaptive.java)

at org.apache.dubbo.registry.integration.RegistryProtocol.getRegistry(RegistryProtocol.java:204)

at org.apache.dubbo.registry.integration.RegistryProtocol.export(RegistryProtocol.java:138)

at org.apache.dubbo.rpc.protocol.ProtocolListenerWrapper.export(ProtocolListenerWrapper.java:55)

at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper.export(ProtocolFilterWrapper.java:98)

at org.apache.dubbo.rpc.Protocol$Adaptive.export(Protocol$Adaptive.java)

at org.apache.dubbo.config.ServiceConfig.doExportUrlsFor1Protocol(ServiceConfig.java:512)

at org.apache.dubbo.config.ServiceConfig.doExportUrls(ServiceConfig.java:357)

at org.apache.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:316)

at org.apache.dubbo.config.ServiceConfig.export(ServiceConfig.java:215)

at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:114)

at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:49)

at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)

at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)

at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)

at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:393)

at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:347)

at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:883)

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)

at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:139)

at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:93)

at org.apache.dubbo.demo.provider.Provider.main(Provider.java:29)

I don't understand the core reason for this error. So I can't find the reason,and I hope to get the answer . Thanks.

Issue 2:
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: 2.5.3

Operating System version: xxx

Java version: 1.7

Dubbo admin同步zookeeper服务延迟比较长，请问这是什么原因？？？困扰了好久