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: 2.5.2(test)，but there are many different versions inside the company.

<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.5.2</version>
<exclusions>
<exclusion>
<artifactId>javassist</artifactId>
<groupId>org.javassist</groupId>
</exclusion>
</exclusions>
</dependency>

Operating System version: uname -a

Darwin tes.local 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 x86_64

Java version: java -version ，but there are many different versions（1.6，1.7） inside the company.

java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.161-b12, mixed mode)

Reason

The low version of dubbo does not provide elegant closure of the dubbo service network, so we are compatible with reflection, but now we don't know the number of consumers.

i can get provider bu using reflect,but can't get consumer. Thanks in advance. please

forgive my lame English

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: 2.7.0

Operating System version: macOS Mojave 10.14.3 18D42 x86_64

Java version: 1.8.0_202

Steps to reproduce this issue

boot (https://github.com/guxingke/demo/blob/master/dubbo-demo/p2p-group-bug-demo/src/main/java/com/gxk/demo/boot/BugServerApp.java)

boot (https://github.com/guxingke/demo/blob/master/dubbo-demo/p2p-group-bug-demo/src/main/java/com/gxk/demo/boot/ClientApp.java)

Expected Result

like "Hello dubbo, response from provider: 192.168.136.176:52159"

Actual Result

nothing, but exception.

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

[NettyServerWorker-3-1] INFO org.apache.dubbo.rpc.protocol.dubbo.CallbackServiceCodec - [DUBBO] Not found exported service: com.gxk.demo.service.HelloService:20880 in [test/com.gxk.demo.service.HelloService:20880], may be version or group mismatch , channel: consumer: /192.168.136.176:51666 --> provider: /192.168.136.176:20880, message:RpcInvocation [methodName=hello, parameterTypes=[class java.lang.String], arguments=null, attachments={path=com.gxk.demo.service.HelloService, dubbo=2.0.2, interface=com.gxk.demo.service.HelloService, version=0.0.0}], dubbo version: 2.7.0, current host: 192.168.136.176
org.apache.dubbo.remoting.RemotingException: Not found exported service: com.gxk.demo.service.HelloService:20880 in [test/com.gxk.demo.service.HelloService:20880], may be version or group mismatch , channel: consumer: /192.168.136.176:51666 --> provider: /192.168.136.176:20880, message:RpcInvocation [methodName=hello, parameterTypes=[class java.lang.String], arguments=null, attachments={path=com.gxk.demo.service.HelloService, dubbo=2.0.2, interface=com.gxk.demo.service.HelloService, version=0.0.0}]
at org.apache.dubbo.rpc.protocol.dubbo.DubboProtocol.getInvoker(DubboProtocol.java:223)
at org.apache.dubbo.rpc.protocol.dubbo.CallbackServiceCodec.decodeInvocationArgument(CallbackServiceCodec.java:270)
at org.apache.dubbo.rpc.protocol.dubbo.DecodeableRpcInvocation.decode(DecodeableRpcInvocation.java:134)
at org.apache.dubbo.rpc.protocol.dubbo.DecodeableRpcInvocation.decode(DecodeableRpcInvocation.java:70)
at org.apache.dubbo.rpc.protocol.dubbo.DubboCodec.decodeBody(DubboCodec.java:132)
at org.apache.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:125)
at org.apache.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:85)
at org.apache.dubbo.rpc.protocol.dubbo.DubboCountCodec.decode(DubboCountCodec.java:46)
at org.apache.dubbo.remoting.transport.netty4.NettyCodecAdapter$InternalDecoder.decode(NettyCodecAdapter.java:95)
at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:489)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:428)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:647)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:582)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:499)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:461)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:748)