I am using Hibernate to save my entities to database. For simple example I have two entities:

Car:

@Entity
@Table(name = "car")
public class Car implements Serializable {
    @Id
    @GeneratedValue
    private long id;
    private String name;
    @OneToMany(cascade = CascadeType.PERSIST)
    private List&lt;Wheel&gt; wheelList;

    public Car() {
    }

    public Car(String name, List&lt;Wheel&gt; wheelList) {
        this.name = name;
        this.wheelList = wheelList;
    }


and Wheel:

@Entity
@Table(name = "wheel")
public class Wheel implements Serializable {
    @Id
    @GeneratedValue
    private long id;
    private int size;
    @ManyToOne(cascade = CascadeType.PERSIST)
    private Car car;

    public Wheel() {
    }

    public Wheel(int size, Car car) {
        this.size = size;
        this.car = car;
    }


I am using Spring Framework (MVC) to create REST client, from which I return JSON. 
And now: I created simple @Repository and @Service.

I wanted to try if saving works, so I created simple Car object with its wheel list etc. and then, in @Service layer I have persisted it and returned car object into the controller.

Finally, when i run the url from the controller, I recieve HUGE json, because every Car object has wheel list, and then, every wheel has its car, which again has list, and in list are wheels which has cars and so on.. thats why my JSON is so big.

{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":{"id":1,"name":"SomeName","wheelList":[{"id":1,"size":1,"car":...........


What do i do wrong? How should i solve this problem?

Rest of the code if you need it:(made just for tests, I know about not-well-coded-style here)
Repository:

@Repository
public class TestImpl {
    @PersistenceContext
    private EntityManager entityManager;

    public Car saveCar(Car car){
        entityManager.persist(car);
        return car;
    }
}


Service

@Service
@Transactional
public class TestService {
    @Autowired
    private TestImpl test;

    public Car save(){
        Car car = new Car();
        car.setName("SomeName");
        List&lt;Wheel&gt; list = new ArrayList&lt;Wheel&gt;();
        list.add(new Wheel(1, car));
        car.setWheelList(list);
        test.saveCar(car);
        return car;
    }
}


Controller:

@Controller
public class TestController {
    @Autowired
    private TestService testService;

    @RequestMapping(value = "/los")
    @ResponseBody
    public Car los(){
        return testService.save();
    }
}



Question: Reducing the size of shadows
Answer: You can only change the angle and softness of a Sun lamp's shadow.


  Sun Lamp
  
  A Sun lamp provides light of constant intensity emitted in a single direction. A Sun lamp can be very handy for a uniform clear daylight open-space illumination. In the 3D view, the Sun light is represented by an encircled black dot with rays emitting from it, plus a dashed line indicating the direction of the light.
  
  This direction can be changed by rotating the Sun lamp, like any other object, but because the light is emitted in a constant direction, the location of a Sun lamp does not affect the rendered result (unless you use the “sky &amp; atmosphere” option).


For more control of the shadow you'll need to use another of the available lamp types.