The following issues should be addressed about samples and samples tests:

1. Flakiness in testListLogEntriesSample() test. It sometimes fails because unexpected log entries (from another tests) are listed and assert validation fail
2. Output of the samples tests run contains java.lang.RuntimeException exception:

   java.lang.RuntimeException: ManagedChannel allocation site
           at io.grpc.internal.ManagedChannelOrphanWrapper$ManagedChannelReference.<init>(ManagedChannelOrphanWrapper.java:93)
           at io.grpc.internal.ManagedChannelOrphanWrapper.<init>(ManagedChannelOrphanWrapper.java:53)
           at io.grpc.internal.ManagedChannelOrphanWrapper.<init>(ManagedChannelOrphanWrapper.java:44)
           at io.grpc.internal.ManagedChannelImplBuilder.build(ManagedChannelImplBuilder.java:625)
           at io.grpc.internal.AbstractManagedChannelImplBuilder.build(AbstractManagedChannelImplBuilder.java:264)
           at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.createSingleChannel(InstantiatingGrpcChannelProvider.java:383)
           at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.access$1900(InstantiatingGrpcChannelProvider.java:82)
           at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider$1.createSingleChannel(InstantiatingGrpcChannelProvider.java:239)
           at com.google.api.gax.grpc.ChannelPool.create(ChannelPool.java:72)
           at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.createChannel(InstantiatingGrpcChannelProvider.java:249)
           at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.getTransportChannel(InstantiatingGrpcChannelProvider.java:227)
           at com.google.api.gax.rpc.ClientContext.create(ClientContext.java:205)
           at com.google.api.gax.rpc.ClientContext.create(ClientContext.java:136)
           at com.google.cloud.logging.spi.v2.GrpcLoggingRpc.<init>(GrpcLoggingRpc.java:148)
           at com.google.cloud.logging.LoggingOptions$DefaultLoggingRpcFactory.create(LoggingOptions.java:61)
           at com.google.cloud.logging.LoggingOptions$DefaultLoggingRpcFactory.create(LoggingOptions.java:55)
           at com.google.cloud.ServiceOptions.getRpc(ServiceOptions.java:560)
           at com.google.cloud.logging.LoggingOptions.getLoggingRpcV2(LoggingOptions.java:129)
           at com.google.cloud.logging.LoggingImpl.<init>(LoggingImpl.java:122)
           at com.google.cloud.logging.LoggingOptions$DefaultLoggingFactory.create(LoggingOptions.java:46)
           at com.google.cloud.logging.LoggingOptions$DefaultLoggingFactory.create(LoggingOptions.java:41)
           at com.google.cloud.ServiceOptions.getService(ServiceOptions.java:540)
           at com.example.logging.ListLogEntries.main(ListLogEntries.java:37)
           at com.example.logging.LoggingIT.testWriteLogHttpRequestSample(LoggingIT.java:120)
           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$1.runReflectiveCall(FrameworkMethod.java:59)
           at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
           at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
           at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
           at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:299)
           at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:293)
           at java.util.concurrent.FutureTask.run(FutureTask.java:266)
           at java.lang.Thread.run(Thread.java:748)

3. A sample for the region tag logging_write_log_entry does not exist. Another snippet (LogEntryWriteHttpRequest) is tagged with non-existing logging_write_request_entry instead of logging_write_log_entry_advanced.