Name for parameter binding must not be null or empty! For named parameters you need to use @Param for query method parameters on Java versions
Try this parameter description:
List<ShopOrder> getShopOrder(@Param("id") long id);
Instead of using : po.id = :id just use ?1....
@Query("SELECT NEW com.htd.domain.ShopOrder(po.id, po.po_number, "
+ "po.due_date, po_part.id, po_part.part_quantity, "
+ "part.id, part.part_number, part.part_description, "
+ "part.plasma_hrs_per_part, part.grind_hrs_per_part, "
+ "part.mill_hrs_per_part, part.brakepress_hrs_per_part) "
+ "FROM Po po "
+ "LEFT JOIN po.partList po_part "
+ "LEFT JOIN po_part.part part "
+ "LEFT JOIN po_part.part where po.id = ?1")
List<ShopOrder> getShopOrder(Long id);