JPA Hibernate Change Fetch type from Lazy To Eager for multiple child entities based on condition

Question

Parent Entity

• Product

  public class ProductEntity extends BaseEntity {
  
   private static final long serialVersionUID = 1L;
  
   @Id
   @Column(name = "id", nullable = false)
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long id;
  
   @Column(name = "product_uuid", nullable = false)
   private String uuid;
  
   @Column(name = "sku", nullable = true)
   private Long sku;
  
   @Column(name = "name", nullable = false)
   private String name;
  
   @OneToMany(mappedBy = "product", cascade = CascadeType.ALL, orphanRemoval = true)
   private Set<ProductInfoEntity> infos;
  
   @OneToMany(mappedBy = "product", cascade = CascadeType.ALL, orphanRemoval = true)
   private Set<ProductTaxEntity> taxes;
  }
  

Child Entity

• Info
• Tax

Only few cases child entities required to fetch eagerly. Is there any way to change child entity fetch type from lazy to eager in either of the framework JPARepository/ CriteriaQuery/SQL

Tried almost every solution on stack overflow but every-time code will hit many queries to retrieve child entities

Answer 1

It's called N+1 problem in hibernate, You can solve it by using below methodologies...

-> By using JOIN FETCH
-> By using @EntityGraph and Projection

Because JOIN FETCH will make always single query for multiple tables using join internally.