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Spring / Spring gRPC Interview Questions

What does the @GrpcService annotation do?

@GrpcService marks a class - one that extends a generated *ImplBase base class from your .proto definition - as both a regular Spring-managed bean and a gRPC service that should be registered on the embedded gRPC server.

@GrpcService
public class GreetingService extends GreeterGrpc.GreeterImplBase {

  @Override
  public void sayHello(HelloRequest req, StreamObserver<HelloReply> obs) {
    HelloReply reply = HelloReply.newBuilder()
        .setMessage("Hello " + req.getName())
        .build();
    obs.onNext(reply);
    obs.onCompleted();
  }
}

Conceptually it plays the same role for gRPC that @RestController plays for HTTP endpoints: it tells the framework 'this class implements a service contract and should be exposed automatically,' while still letting the class participate fully in Spring's dependency injection.

What must a class annotated with @GrpcService typically extend?
@GrpcService is conceptually the gRPC equivalent of which Spring MVC annotation?

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