Spring - Hibernate ManyToMany in Restful app - spring

Question

i have my spring app running with two entities Article and Category.
I integrated RestResponses and it works all fine. Next i added a ManyToMany Relationship to these entities and my rest responses return 404.
I will show you my configuration:
DROP TABLE IF EXISTS `articles`;
create table `articles` (
`id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1;
DROP TABLE IF EXISTS `categories`;
create table `categories` (
`id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1;
DROP TABLE IF EXISTS `categories_articles`;
CREATE TABLE IF NOT EXISTS `categories_articles` (
`id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`categoryID` int(11) UNSIGNED NOT NULL,
`articleID` int(11) UNSIGNED NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `categoryArticleID` (`categoryID`, `articleID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1;
ALTER TABLE `categories_articles`
ADD CONSTRAINT `categories_articles_fk_1` FOREIGN KEY (`categoryID`) REFERENCES `categories` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
ADD CONSTRAINT `categories_articles_fk_2` FOREIGN KEY (`articleID`) REFERENCES `articles` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;
Article.java:
#Entity
#Table(name = "articles")
public class Article {
#Id
#Column(name="id")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer id;
#Column(name="name")
private String name;
private List<Category> categories = new ArrayList<Category>();
public Article() {
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
#ManyToMany(mappedBy = "articles")
public List<Category> getCategories() {
return categories;
}
public void setCategories(List<Category> categories) {
this.categories = categories;
}
}
Category.java:
#Entity
#Table(name = "categories")
public class Category {
#Id
#Column(name="id")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer id;
#Column(name="name")
private String name;
private List<Article> articles = new ArrayList<Article>();
public Category() {
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable(
name = "categories_articles",
joinColumns = #JoinColumn(name = "categoryID", referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name = "articleID", referencedColumnName = "id"))
public List<Article> getArticles() {
return articles;
}
public void setArticles(List<Article> articles) {
this.articles = articles;
}
}
And my RestController:
#GetMapping("/rest/categories")
public RestResponse<Category> list() {
List<Category> data = categoryService.list();
RestResponse<Category> restResponse = new RestResponse<Category>(true, data.size(), data);
return restResponse;
}
where RestResponse is just a simple PoJo:
public class RestResponse<T> {
private Boolean success;
private Integer count;
private List<T> data;
public RestResponse(Boolean success, Integer count, List<T> data) {
this.success = success;
this.count = count;
this.data = data;
}
// getters and setters
}
Sooo, as soon as i comment the many-to-many part and load my app, it all works fine.. but when i uncomment the many-to-many part, i get 404..
I have no idea why, could anybody help me with this issue?
thanks and greetings!