Jhipster sample using DTOs

[istibekesi]

I've checked the samlpe projects within this repo, and I have a few questions about the one that says it uses DTOs:
BankAccountResource.java

    @GetMapping("")
    public List<BankAccountDTO> getAllBankAccounts(
        @RequestParam(name = "eagerload", required = false, defaultValue = "true") boolean eagerload
    ) {
        LOG.debug("REST request to get all BankAccounts");
        List<BankAccount> bankAccounts = bankAccountRepository.findAll();
        return bankAccountMapper.toDto(bankAccounts);
    }

How is this generated, what is the JDL being used?
It has DTOs, but why it does not have a "BankAccountService" implementation?

---

UPDATE
I've generated a brand new project with this super simple JDL:

entity BankAccount {
	bankAccount String
}

// Use Data Transfer Objects (DTO)
dto * with mapstruct

// Set service options to all except few
// service all with serviceImpl except Employee, Job

It generates a BankAccountService and does the mapping in the service layer, not in the controller.
Why the sample project above is different?