Differences Between get() and load() Methods in Hibernate

What is the difference between get and load method in Hibernate?

In Hibernate, both the get() and load() methods are used to retrieve entities from the database, but they have some important differences in their behavior:

1. Return Type:

• get(): This method returns the actual entity object if it exists in the database. If the entity is not found, it returns null.
• load(): This method returns a proxy object of the entity. If the entity does not exist, it throws an ObjectNotFoundException when you try to access a property of the proxy.

2. Loading Behavior:

• get(): It immediately hits the database to retrieve the entity. If the entity is found, it returns the entity; if not, it returns null.
• load(): It does not hit the database immediately. Instead, it returns a proxy object that represents the entity. The actual database call is made only when a method is called on the proxy that requires the entity to be loaded (e.g., accessing a property).

3. Use Cases:

• get(): Use this method when you want to ensure that you either get the entity or know that it does not exist (i.e., you can handle the null case).
• load(): Use this method when you are sure that the entity exists and you want to take advantage of lazy loading. It is more efficient in scenarios where you are certain that the entity will be accessed later.

4. Exceptions:

• get(): Does not throw an exception if the entity is not found; it simply returns null.
• load(): Throws an ObjectNotFoundException if the entity does not exist when you try to access it.

Example:

Session session = sessionFactory.openSession();

// Using get()
MyEntity entity1 = session.get(MyEntity.class, id);
if (entity1 != null) {
    // Entity exists
} else {
    // Entity does not exist
}

// Using load()
MyEntity entity2 = session.load(MyEntity.class, id);
try {
    // Accessing a property will trigger loading the entity
    String property = entity2.getSomeProperty();
} catch (ObjectNotFoundException e) {
    // Handle the case where the entity does not exist
}

Summary:

• Use get() when you want to retrieve an entity and handle the case where it might not exist.
• Use load() when you want to work with a proxy and are confident that the entity exists, taking advantage of lazy loading.