What are the differences between data loading strategies in Hibernate, and what are their features?

In Hibernate, there are two main data loading strategies: eager and lazy loading.

• Eager loading loads related entities immediately along with the main entity. This is convenient when related data is definitely needed, but can lead to excessive queries and reduced performance.

• Lazy loading loads related entities only upon first access. This conserves resources but can cause the "N+1 query" problem if not optimized.

Example annotation in Java:

@Entity
public class User {
    @OneToMany(fetch = FetchType.LAZY)
    private Set<Order> orders;
}

The choice of strategy depends on the specific use case and performance requirements.