This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori 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.