public void joinToChatRoom(Token token, UserId userId, ChatRoomId chatRoomId) throws AuthenticationException, UserNotFoundException, ChatRoomNotFoundException { LOG.info(format("Join user with id[%d] into chat-room with id[%d].", userId.id, chatRoomId.id)); ChatRoom chatRoom = getChatRoom(chatRoomId); User user = getUser(userId); user.getChatRooms().add(chatRoom); userRepository.save(user); LOG.info( format( "Joined user with id[%d] into chat-room with id[%d] was successfully.", userId.id, chatRoomId.id)); }