I have some questions about grouping classes in package. As mentioned in the requirement, we have to put classes related to database to package suncertify.db. If I have a class(act as the Data Client mentioned in the requirement) for communicating with server side, do I also need to put it in this package? I also defined a class, where object of this class is used by both the client and server side. If I put this class in suncertify.server, then the client class need to import suncertify.server package. This seems a little bit odd. What's the usual practice for this situation?