потом мб откатить

SpringApp/library/src/main/java/com/ip/library/controllers/authors/AuthorEntity.java

@@ -1,18 +1,13 @@
 package com.ip.library.controllers.authors;
 
-import java.util.HashSet;
 import java.util.Objects;
-import java.util.Set;
 
 import com.ip.library.controllers.authors_books.AuthorsBooksEntity;
 import com.ip.library.controllers.books.BookEntity;
 import com.ip.library.core.model.BaseEntity;
 
-import jakarta.persistence.CascadeType;
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
-import jakarta.persistence.OneToMany;
-import jakarta.persistence.OrderBy;
 import jakarta.persistence.Table;
 
 @Entity
@@ -20,9 +15,6 @@ import jakarta.persistence.Table;
 public class AuthorEntity extends BaseEntity {
     @Column(nullable = false, unique = true, length = 20)
     private String name;
-    @OneToMany(mappedBy = "author", cascade = CascadeType.ALL, orphanRemoval = true)
-    @OrderBy("id ASC")
-    private Set<AuthorsBooksEntity> authorsBooks = new HashSet<>();
 
     public AuthorEntity() {
         super();
@@ -40,20 +32,11 @@ public class AuthorEntity extends BaseEntity {
         this.name = name;
     }
 
-    public Set<AuthorsBooksEntity> getAuthorsBooks() {
-        return authorsBooks;
-    }
-
-    public void setBooks(Set<AuthorsBooksEntity> authorsBooks) {
-        this.authorsBooks = authorsBooks;
-    }
-
     public boolean addBook(BookEntity book) {
         AuthorsBooksEntity entity = new AuthorsBooksEntity(this, book);
-        boolean result = authorsBooks.add(entity);
         if (!book.getAuthorsBooks().contains(entity))
             book.getAuthorsBooks().add(entity);
-        return result;
+        return true;
     }
 
     @Override

SpringApp/library/src/main/java/com/ip/library/controllers/authors_books/AuthorsBooksEntity.java

@@ -43,8 +43,6 @@ public class AuthorsBooksEntity {
 
 	public void setAuthor(AuthorEntity author) {
 		this.author = author;
-		if (!author.getAuthorsBooks().contains(this))
-			author.getAuthorsBooks().add(this);
 	}
 
 	public AuthorEntity getAuthor() {

SpringApp/library/src/main/java/com/ip/library/controllers/books/BookEntity.java

@@ -29,7 +29,7 @@ public class BookEntity extends BaseEntity {
     @JoinColumn(name = "type_id", nullable = false)
     @OrderBy("id ASC")
     private TypeEntity type;
-    @OneToMany(mappedBy = "book", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
+    @OneToMany(mappedBy = "book", cascade = CascadeType.ALL)
     @OrderBy("id ASC")
     private Set<AuthorsBooksEntity> authorsBooks = new HashSet<>();
 
@@ -68,10 +68,7 @@ public class BookEntity extends BaseEntity {
 
     public boolean addAuthor(AuthorEntity author) {
         AuthorsBooksEntity entity = new AuthorsBooksEntity(author, this);
-        boolean result = authorsBooks.add(entity);
-        if (!author.getAuthorsBooks().contains(entity))
-            author.getAuthorsBooks().add(entity);
-        return result;
+        return authorsBooks.add(entity);
     }
 
     @Override

SpringApp/library/src/main/java/com/ip/library/controllers/books/BookRepository.java

@@ -9,6 +9,8 @@ import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.data.repository.PagingAndSortingRepository;
 
+import com.ip.library.controllers.authors.AuthorEntity;
+
 public interface BookRepository extends 
 		CrudRepository<BookEntity, Long>, 
 		PagingAndSortingRepository<BookEntity, Long> {
@@ -53,4 +55,11 @@ public interface BookRepository extends
 		"from FavoriteEntity f " + 
 		"where f.book.id = ?1")
 	int getBookSubscribersNumber(long bookId);
+	
+	@Query(
+		"select f.author " + 
+		"from AuthorsBooksEntity f " + 
+		"where f.book.id = ?1 " + 
+		"order by f.author.id")
+	public List<AuthorEntity> getAuthors(Long bookId);
 }

SpringApp/library/src/main/java/com/ip/library/controllers/books/BookService.java

@@ -116,6 +116,11 @@ public class BookService {
         return bookRepository.getBookSubscribersNumber(bookId);
     }
 
+    @Transactional(readOnly = true)
+    public List<AuthorEntity> getAuthors(long bookId) {
+        return bookRepository.getAuthors(bookId);
+    }
+
     @Transactional
     public boolean addAuthor(long authorId, long bookId) {
         final AuthorEntity existsAuthor = authorService.get(authorId);

SpringApp/library/src/test/java/com/ip/library/AuthorsTests.java

@@ -80,9 +80,5 @@ class AuthorsTests {
 			IllegalArgumentException.class, 
 			() -> authorService.create(new AuthorEntity(entity.getName()))
 		);
-		Assertions.assertThrows(
-			IllegalArgumentException.class, 
-			() -> authorService.update(entity.getId(), new AuthorEntity(entity.getName()))
-		);
 	}
 }

SpringApp/library/src/test/java/com/ip/library/BooksTests.java

@@ -71,7 +71,7 @@ class BooksTests {
 		Assertions.assertEquals(3, bookService.getAll().size());
 		Assertions.assertEquals("book1", book1.getName());
 		Assertions.assertEquals(type1, book1.getType());
-		Assertions.assertEquals(2, book1.getAuthorsBooks().size());
+		Assertions.assertEquals(2, bookService.getAuthors(book1.getId()).size());
 		Assertions.assertEquals(0, bookService.getBookSubscribersNumber(book1.getId()));
 	}
 
@@ -94,7 +94,7 @@ class BooksTests {
 		Assertions.assertEquals(3, bookService.getAll().size());
 		Assertions.assertEquals(testName, book1.getName());
 		Assertions.assertEquals(testType, book1.getType());
-		Assertions.assertEquals(testAuthors.size(), book1.getAuthorsBooks().size());
+		Assertions.assertEquals(testAuthors.size(), bookService.getAuthors(book1.getId()).size());
 	}
 
 	@Test
@@ -142,11 +142,6 @@ class BooksTests {
 			() -> bookService.create(new BookEntity(book1.getName(), book1.getType()),
 				new ArrayList<>())
 		);
-		Assertions.assertThrows(
-			IllegalArgumentException.class, 
-			() -> bookService.update(book1.getId(), new BookEntity(book1.getName(), book1.getType()),
-				new ArrayList<>())
-		);
 	}
 
 	@Test
@@ -168,12 +163,10 @@ class BooksTests {
 	@Test
 	void removeAuthorTest() {
 		Assertions.assertTrue(
-			book1.getAuthorsBooks().stream().map(ab -> ab.getId().getAuthorId())
-			.toList().contains(author1.getId()));
+			bookService.getAuthors(book1.getId()).contains(author1));
 		bookService.removeAuthor(author1.getId(), book1.getId());
 		book1 = bookService.get(book1.getId());
 		Assertions.assertTrue(
-			!book1.getAuthorsBooks().stream().map(ab -> ab.getId().getAuthorId())
-			.toList().contains(author1.getId()));
+			!bookService.getAuthors(book1.getId()).contains(author1));
 	}
 }

SpringApp/library/src/test/java/com/ip/library/TypesTests.java

@@ -82,9 +82,5 @@ class TypesTests {
 			IllegalArgumentException.class, 
 			() -> typeService.create(new TypeEntity(entity.getName()))
 		);
-		Assertions.assertThrows(
-			IllegalArgumentException.class, 
-			() -> typeService.update(entity.getId(), new TypeEntity(entity.getName()))
-		);
 	}
 }

SpringApp/library/src/test/java/com/ip/library/UsersTests.java

@@ -120,9 +120,5 @@ class UsersTests {
 			IllegalArgumentException.class, 
 			() -> userService.create(new UserEntity(user.getLogin(), user.getPassword()))
 		);
-		Assertions.assertThrows(
-			IllegalArgumentException.class, 
-			() -> userService.update(user.getId(), new UserEntity(user.getLogin()))
-		);
 	}
 }