This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
You'll have to be a bit clearer as to what you're asking here; what does "is associated with" mean, exactly?
But perhaps it would help you to know that any method that accepts an A as an argument will automatically accept a B or a C, and any variable of type A can, again, automatically, refer to a B or a C, if you make the assignment.