Spring boot @ResponseBody doesn’t serialize entity id

I recently had the same problem and it’s because that’s how spring-boot-starter-data-rest works by default. See my SO question -> While using Spring Data Rest after migrating an app to Spring Boot, I have observed that entity properties with @Id are no longer marshalled to JSON

To customize how it behaves, you can extend RepositoryRestConfigurerAdapter to expose IDs for specific classes.

import org.springframework.context.annotation.Configuration;
import org.springframework.data.rest.core.config.RepositoryRestConfiguration;
import org.springframework.data.rest.webmvc.config.RepositoryRestConfigurerAdapter;

@Configuration
public class RepositoryConfig extends RepositoryRestConfigurerAdapter {
    @Override
    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
        config.exposeIdsFor(Person.class);
    }
}