#One-to-Many relationship does not working in Spring - spring

Question

I have an Entity Recipe with a relationship OneToMany with Ingredients.
#Entity
public class Recipe {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Long id;
private String name;
#OneToOne(cascade = CascadeType.ALL) // se eliminiamo la Recipe eliminiamo anche notes
private Notes notes;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "recipe")
private Set<Ingredient> ingredients;
#ManyToMany(fetch=FetchType.EAGER, cascade = CascadeType.ALL)
#JoinTable(name = "recipe_category",
joinColumns = #JoinColumn(name = "recipe_id"),
inverseJoinColumns = #JoinColumn(name = "category_id"))
private Set<Category> categories;
...getter and setter...
}
And an Entity Ingredient:
#Entity
public class Ingredient {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String description;
private int amount;
#ManyToOne
private Recipe recipe;
...getter and setter...
}
In order to test it I have used a controller to insert and retrieving all row:
#GetMapping({"","/"})
public List<Recipe> allRecipe() {
return recipeRepository.findAll();
}
#GetMapping("/insert")
public Recipe addRecipe() {
Set<Ingredient> ingredients = new HashSet<>();
ingredients.add(new Ingredient("ingredient-"+Math.random(), 10));
Recipe newRecipe = new Recipe("Recipe-"+Math.random(),
null, ingredients, null);
return recipeRepository.save(newRecipe);
}
The repository is a JPA Repository.
I do not have any errors, but when I try to retrieve an object I get no ingredients even though they are saved on the table (but with recipe_id = null).
How can I solve this problem?

Answer 1

Initialize your ingredients as
#OneToMany(cascade = CascadeType.ALL, mappedBy = "recipe")
private Set<Ingredient> ingredients = new HashSet<>();
Change your your controller to,
#GetMapping("/insert")
public Recipe addRecipe() {
Ingredient ingredient = new Ingredient("ingredient-"+Math.random(), 10));
Recipe newRecipe = new Recipe("Recipe-"+Math.random(),
null, null); //constructor without ingredient arg
newRecipe.getIngredients.add(ingredient);
ingredient.setRecipe(newRecipe);
return recipeRepository.save(newRecipe);
}