This happens when the TablesConfiguration is done.

It's apparently caused because music jar was compiled with netty 4.1, but the version present at runtime is 4.0.

The solution I propose is to add an explicit dependency in mdbc for netty 4.1, which should override the 4.0 version pulled in by cassandra.

Exception (java.lang.AbstractMethodError) encountered during startup: io.netty.util.concurrent.MultithreadEventExecutorGroup.newChild(Ljava/util/concurrent/Executor;[Ljava/lang/Object;)Lio/netty/util/conc
urrent/EventExecutor;
java.lang.AbstractMethodError: io.netty.util.concurrent.MultithreadEventExecutorGroup.newChild(Ljava/util/concurrent/Executor;[Ljava/lang/Object;)Lio/netty/util/concurrent/EventExecutor;