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This seems to be a buggy behavior, to solve it, first try permuting the order of your spark and hadoop dependencies. If that doesn't work, try updating akka and checking if the versions of the libraries you're using are compatible.
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java.lang.VerifyError: (class: org/jboss/netty/channel/socket/nio/NioWorkerPool, method: createWorker signature: (Ljava/util/concurrent/Executor;)Lorg/jboss/netty/channel/socket/nio/AbstractNioWorker;) Wrong return type in function
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)