How to retrieve nested rest data resources generated by @RepositoryRestResource annotation?

I have to entities exposed by spring boot application powered by Spring data REST.

@Entity
@Table(name = "joke")
@Data
public class Joke {

  @Id
  @Column(name = "joke_id")
  private Long id;

  @Column(name = "content")
  private String content;

  @JsonProperty("category")
  @JoinColumn(name = "category_fk")
  @ManyToOne(fetch = FetchType.EAGER)
  private Category category;
}

and category

@Entity
@Table(name = "category")
@Data
public class Category {

  @Id
  @Column(name = "category_id")
  private int id;

  @Column(name = "name")
  private String name;
}

It is working fine and exposing the HAL+Json format. I'm using Traverson client which is working fine:

Traverson client = new Traverson(URI.create("http://localhost:8080/api/"),
        MediaTypes.HAL_JSON);

    HashMap<String, Object> parameters = Maps.newHashMap();
    parameters.put("size", "2");

    PagedModel<JokesDTO> jokes = client
        .follow("jokes")
        .withTemplateParameters(parameters)
        .toObject(new PagedModelType<JokesDTO>() {
        });

    return jokes;

where JokesDTO is:

@Builder(toBuilder = true)
@Value
@JsonDeserialize(builder = JokesDTO.JokesDTOBuilder.class)
@JsonInclude(Include.NON_NULL)
public class JokesDTO {

  private String content;

  @JsonPOJOBuilder(withPrefix = "")
  @JsonIgnoreProperties(ignoreUnknown = true)
  public static class JokesDTOBuilder {

  }
}

I'm new in HAL and HateOS and I would like to achieve 2 things (and question is - is it possible, and how):

1. Base on Traverson client call, how to retrieve category (or link to category) in one call? How to extend what I wrote. And I'm not talking about adding additional @JsonProperty annotation to my class definition.

2. Is it possible to expose the inner query from Spring data REST, so I would be able to get all data with one call, is it possible with @RepositoryRestResource?