How can I structure this program in java?

I would start out cl Car, cl Driver, cl Navigator, cl Team and worry about the Reports later. This is going to be a whole lot easier as interface. I don't see subcling at all, however, you could, conceivably could, abstract cl Participant and build your compareTo( anotherObject ) so everybody has that important feature. You will need Comparable to do the various sorts they are calling for.