bidirectional relationship returning empty set on OneToMany and works only on ManyToOne - spring-boot

Question

i have 2 entities, Category and Feature, each Category has one or many features.
when creating a category along with its features, fetching the new category returns an empty set on the features attribute.
#PostMapping("/sub")
#PreAuthorize("hasRole('ROLE_admin')")
public HttpEntity<CategoryDTO> createSubCategory(#Valid #RequestBody CreateCategory createCategory)
{
Category category = categoryService.create(createCategory,mainCategoryService.one(createCategory.getMainCategory_id()));
featureService.bulkCreate(createCategory.getFeatures(),category);
return ResponseEntity.status(HttpStatus.CREATED).body(modelMapper.map(category,CategoryDTO.class));
}
this is the data that i'm sending:
{"name":"SUB","mainCategory_id":1,"features":{"F1":"SLIDER","F2":"CHECKBOX"}}
and this is the data returned by the controller:
{"id":2,"name":"SUB","mainCategory":{"id":1,"name":"CATEGORY"},"features":[]}
as you can see, the features are empty.
This is the test to create a category with its features:
#Test
public void testIfAdminCanCreateSubCategory_expect201AndMainCategoryIdEqualsTheAssociatedOne() throws Exception {
String category = "{\"name\" : \"CATEGORY\"}";
String sub = "{\"name\":\"SUB\",\"mainCategory_id\":1,\"features\":{\"F1\":\"SLIDER\",\"F2\":\"CHECKBOX\"}}";
mockMvc().with(keycloakAuthenticationToken().authorities("ROLE_admin")).perform(post("/categories").content(category).contentType("application/json"))
.andDo(print())
.andDo(r -> mockMvc().with(keycloakAuthenticationToken().authorities("ROLE_admin"))
.post(sub,"/categories/sub")
.andExpect(status().isCreated())
.andExpect(jsonPath("$.mainCategory.id").value(1))
.andDo(print())
// .andExpect(jsonPath("$.features[0]").value("SLIDER"))
);
//featureService.all().forEach( f -> System.out.println(f.getCategory().getId()));
}
when decommenting the last line, it prints the category id ( which is 2 as shown in the returned data ), meaning that the ManyToOne is working, but not the OneToMany.
My models:
#Entity
#EntityListeners( AuditingEntityListener.class )
#Data
public class Category {
#Id #GeneratedValue(strategy=GenerationType.AUTO) private Long id;
....
#OneToMany(cascade = CascadeType.ALL, mappedBy = "category" , fetch = FetchType.LAZY)
Set<Feature> features = new HashSet<>();
}
#Entity
#Data
public class Feature {
#Id #GeneratedValue private Long id;
private String name;
private FeatureType type;
#ManyToOne Category category;
}
the create method in categoryService:
#Override
public Category create(CreateCategory createCategory, MainCategory mainCategory) {
Category category = new Category();
category.setName(createCategory.getName().toUpperCase());
category.setMainCategory(mainCategory);
return categoryRepository.save(category);
}
the bulkCreate method in the featureService:
#Override
public Feature create(String feature, FeatureType type, Category category) {
Feature f = new Feature();
f.setName(feature);
f.setType(type);
f.setCategory(category);
return featureRepository.save(f);
}
#Override
public void bulkCreate(Map<String, FeatureType> features, Category category) {
features.forEach( (name,type) -> create(name,type,category));
}
myDTOs:
#Data
public class CategoryDTO {
private Long id;
private String name;
private MainCategoryDTO mainCategory;
private Set<FeatureDTO> features;
}
#Data
public class FeatureDTO {
private Long id;
private String name;
private FeatureType type;
}
#Data
public class MainCategoryDTO {
private Long id;
private String name;
}
EDIT 1 :
i've added a method on my categoryService that sets the category features.
#Override
public Category addFeatures(Category category, List<Feature> features) {
category.setFeatures(features);
return categoryRepository.save(category);
}
and on my controller, i added the commented line so i can associate features to the category
#PostMapping("/sub")
#PreAuthorize("hasRole('ROLE_admin')")
public HttpEntity<CategoryDTO> createSubCategory(#Valid #RequestBody CreateCategory createCategory)
{
Category category = categoryService.create(createCategory,mainCategoryService.one(createCategory.getMainCategory_id()));
#category = categoryService.addFeatures(category,featureService.bulkCreate(createCategory.getFeatures(),category));
return ResponseEntity.status(HttpStatus.CREATED).body(modelMapper.map(category,CategoryDTO.class));
}