Lazy Loading

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

Lazy Loading

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

• J2EE Design Patterns
• Patterns of Enterprise Application Architecture