What is the difference between get() and load() methods in Hibernate when retrieving data from a database?

In Hibernate, the methods get() and load() are used to retrieve objects from the database but have different characteristics:

• get(Class<T> clazz, Serializable id):

  • Immediately executes a query to the database.
  • Returns the object or null if the object with such ID is not found.
  • Used when you need to get data right away.

• load(Class<T> clazz, Serializable id):

  • Returns a proxy object without an immediate database query.
  • The database query is only executed upon the first access to the object's properties (lazy loading).
  • If the object with such ID does not exist, an ObjectNotFoundException will be thrown when accessing the proxy.

Example:

// get immediately accesses the database
User user = session.get(User.class, 1);
if (user == null) {
    System.out.println("User not found");
}

// load returns a proxy
User userProxy = session.load(User.class, 1);
// the database query will be executed upon the first call to userProxy.getName()

The choice depends on the situation: if you need to check the existence of an object, it's better to use get(). If the ID is known and the object definitely exists, you can use load() for optimization.