How does Hibernate persistence work?

How does Hibernate persistence work?

Hibernate persist is similar to save (with transaction) and it adds the entity object to the persistent context, so any further changes are tracked. If the object properties are changed before the transaction is committed or session is flushed, it will also be saved into database.

What does EntityManager persist do?

The EntityManager. persist() operation is used to insert a new object into the database. ... The persist operation can only be called within a transaction, an exception will be thrown outside of a transaction. The persist operation is in-place, in that the object being persisted will become part of the persistence context.

Is Hibernate really worth it?

If your project does not have an intensive report generation and/or you're comfortable with ORM mapping, Hibernate is your best choice. Otherwise, I strongly recommend checking out for alternatives. You may find wonderful things outside the mainstream.

Is Hibernate outdated?

No, Hibernate is not deprecated. However, there's now JPA (Java Persistence API), which is a standard API for doing the things that Hibernate does. Note that JPA is just an interface specification. You'll need something that implements JPA, and Hibernate is one of the implementations of JPA.

What is dirty checking in hibernate?

Dirty checking is an essential concept of Hibernate. The Dirty checking concept is used to keep track of the objects. It automatically detects whether an object is modified (or not) or wants to be updated. It also allows a developer to avoid time-consuming database write actions.

Which 2nd level cache is better in hibernate?

Hibernate Second Level Cache

Implementation	read-only	nonstrict-read-write
EH Cache	Yes	Yes
OS Cache	Yes	Yes
Swarm Cache	Yes	Yes
JBoss Cache	No	No

Do I need to close EntityManager?

EntityManagerFactory instances are heavyweight objects. Each factory might maintain a metadata cache, object state cache, EntityManager pool, connection pool, and more. If your application no longer needs an EntityManagerFactory , you should close it to free these resources.

What is difference between persist and merge?

For new entities, you should always use persist , while for detached entities you need to call merge . For managed entities, you don't need any save method because Hibernate automatically synchronizes the entity state with the underlying database record.

Why is Hibernate so bad?

The disadvantage is that it will continue to consume power because of RAM's volatile nature. ... On the other hand, hibernating computers need more time to resume because they have to fetch the data from the hard drives (instead of RAM) and then write these values into RAM, making the whole process more time-consuming.

Why we should not use Hibernate?

If you schema is very simple (less than 8-10 tables) and does not have very complex relationship among them, then hibernate usage will be slightly overkill for this scenario. If you application uses a lot of static data then caching would be a good option and hibernate support caching transparently.

What is the difference between save and persist in hibernate?

• Another difference between save and persist method in Hibernate is behavior on outside of transaction boundaries. There is no boundary of transaction for save () method because it returns an identifier so that an insert query is executed immediately to get the identifier.

Is Hibernate session object is thread-safe?

• Hibernate Session objects are not thread safe , so we should not use it in multi-threaded environment. We can use it in single threaded environment because it's relatively faster than opening a new session.

Do any birds hibernate?

• Mostly no. For the most parts birds do not hibernate because they have adapted other strategies for surviving the cold winters, such as migration. Many kinds of birds do not leave the Rocky Mountains during the winter, such as the black capped chickadees.

What is Session object in hibernate?

• Hibernate - Sessions. A Session is used to get a physical connection with a database. The Session object is lightweight and designed to be instantiated each time an interaction is needed with the database. Persistent objects are saved and retrieved through a Session object.