code: public static <E, D> JpaRepositoryConfig.Builder<D> builder(Class<E> entityClass, Class<D> dtoClass,
                                                                  JpaMapper<E, D> mapper) {
          JpaRepositoryConfig.Builder<D> builder = new JpaRepositoryConfig.Builder<>();
          builder.entityClass = entityClass;
          builder.resourceClass = dtoClass;
          builder.mapper = mapper;
          return builder;
      }
docs: Prepares a builder to configure a jpa document for the given entity class which is
  mapped to a DTO with the provided mapper.
  
  @param <E>         entity type
  @param <D>         dto type
  @param entityClass to use
  @param dtoClass    to expose
  @param mapper      to convert entity to dto and back
  @return builder