added a method description

src/main/java/com/libraryman_api/book/BookService.java

@@ -112,6 +112,17 @@ public void deleteBook(int bookId) {
                 .orElseThrow(() -> new ResourceNotFoundException("Book not found"));
         bookRepository.delete(book);
     }
+    /**
+     * Converts a Book entity to a BookDto object.
+     *
+     * <p>This method takes a Book entity and transforms it into a BookDto object for
+     * data transfer between application layers. It maps all relevant book details,
+     * including book ID, publisher, published year, title, author, genre, ISBN,
+     * and copies available, from the entity to the DTO.</p>
+     *
+     * @param book the entity object containing book information
+     * @return a BookDto object with data populated from the entity
+     */
 
     public BookDto EntityToDto(Book book){
         BookDto bookDto= new BookDto();
@@ -125,6 +136,18 @@ public BookDto EntityToDto(Book book){
         bookDto.setCopiesAvailable(book.getCopiesAvailable());
         return bookDto;
     }
+    /**
+     * Converts a BookDto object to a Book entity.
+     *
+     * <p>This method takes a BookDto object and converts it into a Book entity for
+     * use in database operations. It maps all relevant book details, including
+     * book ID, author, genre, publisher, published year, title, ISBN, and copies
+     * available, from the DTO to the entity.</p>
+     *
+     * @param bookDto the DTO object containing book information
+     * @return a Book entity with data populated from the DTO
+     */
+
 
     public Book DtoToEntity(BookDto bookDto){
          Book book= new Book();

src/main/java/com/libraryman_api/borrowing/BorrowingService.java

@@ -291,6 +291,19 @@ public Page<BorrowingsDto> getAllBorrowingsOfMember(int memberId, Pageable pagea
             throw new InvalidSortFieldException("The specified 'sortBy' value is invalid.");
         }
     }
+    /**
+     * Converts a BorrowingsDto object to a Borrowings entity.
+     *
+     * <p>This method takes a BorrowingsDto object and transforms it into a Borrowings
+     * entity for use in database operations. It maps all relevant borrowing details
+     * from the DTO, including borrow date, member information, fine, return date,
+     * due date, and book details. It also retrieves and converts related entities
+     * such as Member and Book using respective service methods.</p>
+     *
+     * @param borrowingsDto the DTO object containing borrowing information
+     * @return a Borrowings entity with data populated from the DTO
+     */
+
 
     public Borrowings DtoToEntity(BorrowingsDto borrowingsDto){
         Borrowings borrowings = new Borrowings();
@@ -303,6 +316,19 @@ public Borrowings DtoToEntity(BorrowingsDto borrowingsDto){
         borrowings.setBorrowingId(borrowingsDto.getBorrowingId());
         return borrowings;
     }
+    /**
+     * Converts a Borrowings entity to a BorrowingsDto object.
+     *
+     * <p>This method takes a Borrowings entity and converts it into a BorrowingsDto
+     * object for data transfer between application layers. It maps all necessary
+     * borrowing details from the entity, including borrowing ID, fine, borrow date,
+     * return date, due date, and related Member and Book entities, converting them
+     * into DTOs using respective service methods.</p>
+     *
+     * @param borrowings the entity object containing borrowing information
+     * @return a BorrowingsDto object with data populated from the entity
+     */
+
 
     public BorrowingsDto EntityToDto(Borrowings borrowings){
         BorrowingsDto borrowingsDto = new BorrowingsDto();

src/main/java/com/libraryman_api/member/MemberService.java

@@ -135,6 +135,17 @@ public void deleteMember(int memberId) {
         notificationService.accountDeletionNotification(member);
         memberRepository.delete(member);
     }
+    /**
+     * Converts a MembersDto object to a Members entity.
+     *
+     * <p>This method takes a MembersDto object and transforms it into a Members entity
+     * to be used in database operations. It maps all relevant member details from
+     * the DTO, including member ID, role, name, email, password, and membership date.</p>
+     *
+     * @param membersDto the DTO object containing member information
+     * @return a Members entity with data populated from the DTO
+     */
+
 
     public Members DtoEntity(MembersDto membersDto){
         Members members= new Members();
@@ -146,6 +157,18 @@ public Members DtoEntity(MembersDto membersDto){
         members.setMembershipDate(membersDto.getMembershipDate());
         return members;
     }
+    /**
+     * Converts a Members entity to a MembersDto object.
+     *
+     * <p>This method takes a Members entity object and converts it into a MembersDto
+     * object to be used for data transfer between layers. It maps all necessary
+     * member details, including member ID, name, role, email, password, and membership
+     * date, from the entity to the DTO.</p>
+     *
+     * @param members the entity object containing member information
+     * @return a MembersDto object with data populated from the entity
+     */
+
 
     public MembersDto EntityToDto(Members members){
         MembersDto  membersDto= new MembersDto();