get() vs. load() method

In Hibernate, get and load both are used for data retrieval

User user = (User) session.get(User.class, userID);

User user = (User) session.load(User.class, userID);

The identifier uniquely identifies a single instance of a class.

Retrieval by identifier can use the cache when retrieving an object, avoiding a database hit if the object is already cached.

Difference in return value if record doesn't found

get() : Returns null if the object can’t be found.

load() : If can’t find the object in the cache or database, an exception is thrown. The load() method never returns null.

get() : Never returns a proxy.

load() : May return a proxy instead of a real persistent instance.

A proxy is a placeholder instance of a runtime-generated subclass (through cglib or Javassist) of a mapped persistent class, it can initialize itself if any method is called that is not the mapped database identifier getter-method.

Choosing between get() and load()

It's easy !

If you’re certain the persistent object exists, and non-existence would be considered exceptional, load() is a good option.

If you aren’t certain there is a persistent instance with the given identifier, use get() and test the return value for null.

Using load() has a further implication :

The application may retrieve a valid reference (a proxy) to a persistent instance without hitting the database to retrieve its persistent state. So load() might not throw an exception when it doesn’t find the persistent object in the cache or database; the exception would be thrown later, when the proxy is accessed.