Yes, you can make your Spring service classes final, and it’s a good practice to do so if you don’t intend for them to be extended. Making a class final explicitly communicates that it is not designed for inheritance, and it can bring several benefits:

1. Security: Final classes cannot be subclassed, which can prevent unintended or malicious modifications to the behavior of the class through inheritance.
2. Performance: The compiler and runtime can make certain optimizations for final classes, as they don’t need to consider potential subclasses.
3. Design Clarity: Declaring a class as final provides clarity to other developers working on the code that the class is not meant to be extended.
4. Predictable Behavior: Final classes provide a level of predictability, making it easier to reason about the behavior of the code.

In the context of Spring services, it’s a common practice to make service classes final, especially if they are designed to be standalone components that encapsulate specific business logic or functionality. The final keyword is used to indicate that the class should not be extended, and it helps prevent unintentional misuse or modification of the class by subclassing.

Here’s an example of how you might declare a Spring service class as final:

@Service
public final class MyService {
    // Dependencies and methods go here.
}

In the example above, the @Service annotation indicates that the class is a Spring service component. Making it final reinforces the intent that it should not be extended.