Returning a Collection with Generic Projections so multiple Projections can be selected in Spring Data JPA

Question

I am trying to be able to select from multiple projections as return type in a collection when accessing a method in a jpa repository

I have come across this thread, however its information is not really sufficient: Spring Data Jpa generic projection findAll

It seems like i cant use a list, but i dont understand why and its not explained in that thread.

I want to get the following code to work:

public interface ThemingRepository extends JpaRepository<ThemeData, Long> {
  <T> List<T> findByOrderByIdAsc(Class<T> type);
}

  @Transactional
  public byte[] findBackgroundImage() {

    var list = themingRepository.findByOrderByIdAsc(ThemeDataBackgroundImage.class);
    if (list.isEmpty()) {
      throw new NoThemeColorsSetException();
    }
    return list.get(0).getBackgroundImage();
  }

  @Transactional
  public byte[] findLogoImage() {

    var list = themingRepository.findByOrderByIdAsc(ThemeDataLogoImage.class);
    if (list.isEmpty()) {
      throw new NoThemeColorsSetException();
    }
    return list.get(0).getLogo();
  }

  @Transactional
  public ThemeDataColors findThemeColors() {

    var list = themingRepository.findByOrderByIdAsc(ThemeDataColors.class);
    if (list.isEmpty()) {
      throw new NoThemeColorsSetException();
    }
    return list.get(0);
  }

An example projection:

public interface ThemeDataBackgroundImage {
  byte[] getBackgroundImage();
}