The CDI specification adds a new feature to use CDI into a code that works outside the CDI container.
Though this feature does not use those CDI can still use the callback (@PostConstruct and @PreDestroy) and injection with @Inject record within its class. Keep in mind that these annotations are not part of the CDI specifications but of @Inject.

For example, this class included in a non-CDI archive will work anyway:

public class Car {
   @Inject
   SomeClass someInstance;
   @PostConstruct
   public void init()  {
      ...
   }
   @Predestroy
   public void cleanUp() {
      ...
   }
}

Here's how we can obtain an instance of an object through Unmanaged:

Unmanaged<Car> unmanaged = new Unmanaged(Car.class);
UnmanagedInstance<Car> unmanagedCar = unmanaged.newInstance();
Car car = unmanagedCar.produce().inject().postConstruct().get();