Entity Lifecycle

In JPA (Java Persistence API), the entity lifecycle refers to the process from when an entity is created until it is destroyed.

4 States of Entity Lifecycle

  1. New/Transient:

    • A new entity is created, but it is not yet managed by an EntityManager.
    • It is not stored in the database and is not managed by the persistence context.
    • Entities created with the new keyword are in the transient state.

  2. Managed:

    • The state in which an entity is managed by an EntityManager, and is stored in the persistence context.
    • The entity is synchronized with the database and is managed by the persistence context.
    • You can make an entity managed by using the persist() method.

  3. Detached:

    • The state in which an entity is not managed by a persistence context.
    • It is separated from the managed state and is not managed by the persistence context.
    • You can make an entity detached by using the detach() method.

  4. Removed:

    • The state in which an entity is marked as deleted in the persistence context, but not yet deleted in the database.
    • It will be deleted from the database when the next transaction is committed.
    • You can make an entity removed by using the remove() method.

Conclusion

The entity lifecycle consists of four states: new/transient, managed, detached, and removed. Depending on the state of the entity, actions such as storing in the persistence context or deleting are performed.