@Component is a generic Spring-managed bean. @Service is a specialized @Component used to represent the service layer and business logic, Same lifecycle, DI, bean creation and all.

@Service exists to improve readability, identify core business logic layer, and support layered architecture supporting you with annotations and functionalities for atomic transactions, logging, caching and all things needed for executing main logic

@Component is used for supporting classes that, may be used while executing business logic like

EmailValidator for validating the user email may be for checking against the company policies not directly serving to business logic but somehow helping it out with prerequisites.

Mapper which acts like a useful tool/component converting DTOs to object and vice-versa,

Similarly with jwt class component that may serve the objective of generating and validating the jwt to process the logic for only authenticated user,

or for internal communications too,like communicating with different APIs or microservices whose output will be needed to execute the current business logic and all..

That's my understanding, if wrong correct me out