The errors reported when an object does not implement an interface that implements java.rmi.Remote are misleading, e.g:

error: Stubs are only needed for classes that implement RemoteObject interfaces;
Class example.stock.StockServer does not, remote invocation is supported by
the stubs for class java.rmi.server.RemoteObject.

"RemoteObject interfaces" should be "the interface java.rmi.Remote". Also the error should not report java.rmi.server.RemoteObject as supporting remote invocation because it does not. There are other messages in this same category that also need to be fixed.