Hibernate Lazy Object With No Relations

Question

I have an Hibernate object as follows:

@Entity
@Table(name="SOME_TABLE")
public class SomeEntity {

private Long id;
private String someInfo;

@Id
@Column(name = "ID")
public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

@Column(name = "SOME_INFO")
public String getSomeInfo() {
    return someInfo;
}

public void setSomeInfo(String someInfo) {
    this.someInfo = someInfo;
}
}

When loading the object using the following code:

sessionFactory.getCurrentSession().load(getEntityClass(), id);

The object's fields are not loaded, instead a proxy object is returned, and the actual fields are loaded only when I explicitly call them by their getter method. To the best of my knowledge, plain fields (primitives, strings) should be loaded eagerly. Why does the fields, which are not relations or Collections are loaded lazily? is there any way to ask Hibernate to load them eagerly? This is problematic for me as I use this object as the return value of a Spring REST application, and then I get a could not initialize proxy - no Session exception.

afaik, hibernate loads properties eagerly by default. This behavior can be changed using "bytecode enhancement". Could this be some how set as the default in your project? check this answer for enabling lazy loading of properties stackoverflow.com/questions/19610085/…. — Mustafa
– Mustafa, Commented Jan 31, 2017 at 18:11

Naros · Accepted Answer · 2017-01-31 18:33:23Z

2

The reason you obtain a proxy is because the Session#load contract is permitted to return a proxy as a placeholder without ever querying the database for the specified object. This is also why it's crucial that the provided identifier for which you wish to load exists as you'll run into unexpected ObjectNotFoundException errors later on if so.

What you want to use is Session#get which is guaranteed to query the database and will not return a proxy, thus those basic attributes you mentioned will be eagerly loaded as you would expect.

For example:

final Comment comment = new Comment( "This is a comment" );
comment.setOwner( session.load( Product.class, productId ) );
session.save( comment );

The benefit here is that the Product isn't fully initialized. We create a persistent proxy with the specified productId value and associate it as the owner of the comment. This is sufficient when we persist the new Comment to make the foreign-key relationship occur without having to actually load the state of Product, avoiding unnecessary overhead.

answered Jan 31, 2017 at 18:33

Naros

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1 Comment

zuckermanori Over a year ago

Thank you @Naros this is what i missed

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