entity | Expose API fields for endpoint user | REST library

I am using class based projection with constructor expressions. here is a sample code form my work

I have a for loop which calls a few times to database API. These calls return data for a menu, but when I try to map array I can't do it because array is empty.

First scenario:

I have two tables:

1. Car_company which has the attributes of: C_id (primary key), C_name
2. Car_model which has the attributes of: Com_id (referenced to C_id of Car_company), Model_year Warranty

I wish to access both of these tables individually and also I would like to perform a join operation on them and display all of the car_models along with their car_company name. I tried using both JPQL and native query but nothing worked. I also made sure to use the OneToMany and ManyToOne associations but I ended up getting infinite nesting,i.e, the models have car_company as field, this inturn has car_models as a list, and this keeps going. Please help me with entity classes and DAOs.

message = ""

Validation failed for classes [com.PointsSystem.entity.Membership] during persist time for groups [javax.validation.groups.Default, ]\nList of constraint violations:[\n\tConstraintViolationImpl{interpolatedMessage='请输入正确的手机号(11位)', propertyPath=cellPhone, rootBeanClass=class com.PointsSystem.entity.Membership, messageTemplate='请输入正确的手机号(11位)'}\n\tConstraintViolationImpl{interpolatedMessage='lastName 不能为空', propertyPath=lastName, rootBeanClass=class com.PointsSystem.entity.Membership, messageTemplate='lastName 不能为空'}\n]

""

I do not want to print this message on my web app, I need to get the key word "interpolatedMessage" which contains Chinese characters. How can I do that? This message was get when i use e.getMessage, e ment a Exception

I'm creating a generic repository as follows:

I'm trying to make a relation between my Book entity and a list of languages that I retrieve through a service. In my database, each book has a: ID, TITLE, CATEGORY_ID (FK), LANG_ID

Book.java:

I am trying to use JOOQ code generation from JPA Entity. I have already created a dedicated maven module where the code will be generated which has dependency on a module containing all entities as well code generation plugin with of jooq.

To add more clarify on project structure, here are the modules:(The names are made up but the structure reflects the current project i am working on)

I am currently trying to write some ECS in C++. Inside my ECS (Entity component system), I have a set of entities which all have a set of components. Like a position, rotation, etc.. What I want to do is implement a function which returns an iterator to iterate over the entities which fullfill a few requirements. These requirements are grouped into the following categories:

1. required
2. requires_one
3. excludes

Ideally, I would call the function like this:

I build my Nestjs project with nestjsx to create Restful api. My customer.controller.ts