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Lazy Loading

Performance Idiom

Intent

Lazy loading is a design pattern commonly used to defer initialization of an object until the point at which it is needed. It can contribute to efficiency in the program's operation if properly and appropriately used.

Class diagram

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Applicability

Use the Lazy Loading idiom when

  • eager loading is expensive or the object to be loaded might not be needed at all

Real world examples

  • JPA annotations @OneToOne, @OneToMany, @ManyToOne, @ManyToMany and fetch = FetchType.LAZY

Credits