This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
If classroom.getStudentSet() returns just a Set, without generics, then no. The only thing to do is either change the classroom class, or use @SuppressWarnings("unchecked") on that variable or the method/constructor.