Can or should a Service layer be a Spring bean?
If so, how should it be got from a calling application, a consumer of a service?
Because the consumer must be aware that such a bean exists, so it in any case must use Spring
to make use of Service methods.
Yes, It is always nice to configure service beans as spring beans. In the web layer you need to take care of instantiating the needed service objects. Another option is to make the web layer classes also as spring beans and inject the necessary service layer spring beans. From the testing point of view also, this type of design is very helpful when we use Spring testing framework.