CODEWITHSUNDEEP
javahibernatejpafetchjpa-2.1
masber
masber

Reputation: 3067

hibernate/jpa ignoring LAZY FETCHING in @XxxToOne relationship

I am using hibernate 5 as a JPA implementation and I have an issue with a @OneToMany bidirectinal relationship.

These are my entities:

@Entity(name = "product_item")
public class ProductItem {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "receptacle")
    private Receptacle receptacle;

...

}

@Entity(name = "receptacle")
public class Receptacle {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @OneToMany(mappedBy = "receptacle", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    private Set<ProductItem> productItems = new HashSet<>();

...

}

I would like this relationship to be lazy in both directions as I want to manually fetch the data through FETCH JOIN like the query below: 

String query = "SELECT " 
            + " DISTINCT r" 
            + " FROM" 
            + " receptacle r"
            + " JOIN FETCH product_item pi ON r.id = pi.receptacle.id"
            + " JOIN ereturn er ON er.id = pi.ereturn.id"
            + " WHERE"
            + " r.masterCrossDock IS NULL";

But my problem is that hibernate is ignoring the @ManyToOne(fetch = FetchType.LAZY) hence Jackson breaks due to Infinite recursion (StackOverflowError) through reference chain as shown below:

org.glassfish.jersey.server.internal.process.MappableException: com.fasterxml.jackson.databind.JsonMappingException: Infinite recursion (StackOverflowError) (through reference chain: returnitRest.Receptacle["productItems"]->org.hibernate.collection.internal.PersistentSet[0]->returnitRest.ProductItem["receptacle"]->returnitRest.Receptacle["productItems"]->org.hibernate.collection.internal.PersistentSet[0]->returnitRest.ProductItem["receptacle"]- ...

QUESTION 1: How could I tell hibernate not to fetch the @ManyToOne relationship direction?

QUESTION 2: If what I am trying to do is not possible, why?

QUESTION 3: What would be the best way of doing what I am trying to do?

thank you very much

Upvotes: 3

Views: 1881

Answers (1)

osama yaccoub
osama yaccoub

Reputation: 1866

According to the JPA specs, LAZY loading is a hint that the provider can totally ignore , It's totally up to the provider (hibernate here) to either consider it or ignore it (given also that single-valued associations -OneToOne and ManyToOne - are eagerly loaded by default).... So you can't rely on it.

Concerning the recursive problem, check my post here , I had a similar issue with gson and this is how I solved it

Upvotes: 0

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