```
An identity for the admin user "admin" already exists in the wallet
An identity for the user "appUser" already exists in the wallet
Oct 28, 2021 10:18:17 AM io.grpc.internal.SerializingExecutor run
SEVERE: Exception while executing runnable io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed@59950e4a    
java.lang.NullPointerException
        at org.hyperledger.fabric.sdk.Channel.getExecutorService(Channel.java:1981)
        at org.hyperledger.fabric.sdk.Peer.getExecutorService(Peer.java:134)
        at org.hyperledger.fabric.sdk.Peer.reconnectPeerEventServiceClient(Peer.java:379)
        at org.hyperledger.fabric.sdk.PeerEventServiceClient$1.onError(PeerEventServiceClient.java:288)
        at io.grpc.stub.ClientCalls$StreamObserverToCallListenerAdapter.onClose(ClientCalls.java:442)
        at io.grpc.PartialForwardingClientCallListener.onClose(PartialForwardingClientCallListener.java:39)
        at io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:23)
        at io.grpc.ForwardingClientCallListener$SimpleForwardingClientCallListener.onClose(ForwardingClientCallListener.java:40)
        at io.grpc.internal.CensusStatsModule$StatsClientInterceptor$1$1.onClose(CensusStatsModule.java:700)
        at io.grpc.PartialForwardingClientCallListener.onClose(PartialForwardingClientCallListener.java:39)
        at io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:23)
        at io.grpc.ForwardingClientCallListener$SimpleForwardingClientCallListener.onClose(ForwardingClientCallListener.java:40)
        at io.grpc.internal.CensusTracingModule$TracingClientInterceptor$1$1.onClose(CensusTracingModule.java:399)
        at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:510)
        at io.grpc.internal.ClientCallImpl.access$300(ClientCallImpl.java:66)
        at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.close(ClientCallImpl.java:630)
        at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.access$700(ClientCallImpl.java:518)
        at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInternal(ClientCallImpl.java:692)        
        at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:681)       
        at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
        at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:123)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)

Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 34.931 sec <<< FAILURE!
testFabCar(org.example.ClientTest)  Time elapsed: 34.873 sec  <<< ERROR!
org.hyperledger.fabric.gateway.ContractException: No valid proposal responses received. 2 peer error responses: Channel Channel{id: 1, name: mychannel} Sending proposal with transaction: 2821bb263c90c67c0c4bb8ad94e93a6a34d0f72e8014bd19e8e69686781384d7 
to Peer{ id: 5, name: peer0.org2.example.com:9051, channelName: mychannel, url: grpcs://localhost:9051, mspid: Org2MSP} failed because of: gRPC failure=Status{code=UNAVAILABLE, description=io exception, cause=io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information: localhost/0:0:0:0:0:0:0:1:9051
Caused by: java.net.ConnectException: Connection refused: no further information
        at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
        at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
        at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:327)
        at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:336)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:685)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:632)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:549)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:511)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:918)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Thread.java:745)
}; Channel Channel{id: 1, name: mychannel} Sending proposal with transaction: 2821bb263c90c67c0c4bb8ad94e93a6a34d0f72e8014bd19e8e69686781384d7 to Peer{ id: 7, name: peer0.org1.example.com:7051, channelName: mychannel, url: grpcs://localhost:7051, mspid: Org1MSP} failed because of: gRPC failure=Status{code=UNAVAILABLE, description=io exception, cause=io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information: localhost/0:0:0:0:0:0:0:1:7051
Caused by: java.net.ConnectException: Connection refused: no further information
        at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
        at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
        at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:327)
        at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:336)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:685)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:632)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:549)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:511)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:918)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Thread.java:745)
}
        at org.hyperledger.fabric.gateway.impl.TransactionImpl.validatePeerResponses(TransactionImpl.java:196)
        at org.hyperledger.fabric.gateway.impl.TransactionImpl.submit(TransactionImpl.java:93)
        at org.hyperledger.fabric.gateway.impl.ContractImpl.submitTransaction(ContractImpl.java:50)
        at org.example.ClientApp.main(ClientApp.java:53)
        at org.example.ClientTest.testFabCar(ClientTest.java:15)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
        at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
        at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
        at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
        at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
        at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
        at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
        at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
        at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
        at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
        at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)


Results :

Tests in error:
  testFabCar(org.example.ClientTest): No valid proposal responses received. 2 peer error responses: Channel Channel{id: 1, name: mychannel} Sending proposal with transaction: 2821bb263c90c67c0c4bb8ad94e93a6a34d0f72e8014bd19e8e69686781384d7 to Peer{ id: 5, name: peer0.org2.example.com:9051, channelName: mychannel, url: grpcs://localhost:9051, mspid: Org2MSP} failed because of: gRPC failure=Status{code=UNAVAILABLE, description=io exception, cause=io.netty.channel.AbstractChannel$AnnotatedConnectExcept(..) Connection refused: no further information: localhost/0:0:0:0:0:0:0:1:9051
```