Confusing error messages for a wrong user main

When supplying a wrong user_main like this

-user_main XXX

Nemo outputs the following error message that suggests networking errors (I've replace the actual IPs/ports with ...), which is obviously very confusing.

Caused by: java.lang.RuntimeException: org.apache.reef.tang.exceptions.InjectionException: Could not invoke constructor: new ClientRPC(TransportFactory = [ClassNodeImpl 'org.apache.reef.wake.remote.transport.netty.MessagingTransportFactory']: org.apache.reef.wake.remote.transport.netty.MessagingTransportFactory(org.apache.reef.wake.remote.address.LocalAddressProvider),  = org.apache.reef.wake.remote.transport.netty.MessagingTransportFactory@3bcd05cb, LocalAddressProvider = [ClassNodeImpl 'org.apache.reef.wake.remote.address.HostnameBasedLocalAddressProvider']: org.apache.reef.wake.remote.address.HostnameBasedLocalAddressProvider(),  = HostnameBasedLocalAddressProvider:....., String ClientSideRPCServerHost = ....., Integer ClientSideRPCServerPort = .....)

You can reproduce this bug with the following command:

./bin/run_beam.sh -job_id mr_default -executor_json `pwd`/examples/resources/beam_test_executor_resources.json -optimization_policy org.apache.nemo.compiler.optimizer.policy.DefaultPolicy -user_main XXX -user_args "`pwd`/examples/resources/test_input_wordcount `pwd`/examples/resources/test_output_wordcount"