Make Spring Service Classes Final?

Question

Can I make the spring service classes final? Is there any harm doing that? Nobody is going to extend the class. Is there any issue?

public final class MyService {
   // Depedencies go here.
}

Answer 1

Don't make them final. If you use any AOP (including transaction support) on concrete classes, spring will use CGLIB to dynamically extend your class in order to make a proxy. And the requirement for CGLIB to work is to have your classes non-final. Otherwise an exception will be thrown.