Java JPA Projection in Repository— No property found for type

The Problem

You have the JPA projection by interface like this

public interface PaymentSummaryReponse {
  String getCode();
  BigDecimal getAmount();
}

Then you got the problem when compile

No property 'YourMethod' found for type 'YourEntity'

You even try to change the method name to foo to see what is the problem.

public interface PaymentSummaryRepository extends JpaRepository<PaymentSummary, Integer> {
    List<PaymentSummaryResponse> foo();
}

Solution : Naming Convention

You need to name the method to be the same with JPA method

For example, findByFoo or other convention

Because Spring Boot treat the projection as an ‘Add-on’ to these existing method.

In my case, findAll will be findAllProjectedBy

public interface PaymentSummaryRepository extends JpaRepository<PaymentSummary, Integer> {
    List<PaymentSummaryResponse>  findAllProjectedBy();
}