How do the normal and lazy loading modes in JPA differ?

In JPA, fetch modes determine when related entities or collections are loaded from the database:

• EAGER loading — related data is loaded immediately along with the main entity. This is convenient when related data is always needed, but can lead to excessive queries and reduced performance.

• LAZY loading — related data is loaded only upon first access in the code. This conserves resources, especially if related data is not always required.

Example:

@Entity
public class Order {
    @OneToMany(fetch = FetchType.LAZY)
    private List<Item> items;
}

Here, the list of items will be loaded from the database only when order.getItems() is called.