RecapDifficulty: Advanced1 min

Recap: The JPA Entity Lifecycle

Four states, the operations between them, insert timing, detached changes, and refresh or clear.

The JPA entity lifecycle comes down to the five ideas below, each listed with the card that covers it.

What the topic established, and which card it was on
The idea	Where
An entity is transient, managed, detached or removed, and only managed changes are written	JPA Entity States: Transient, Managed, Detached and Removed
`contains()` shows the real state; `merge()` returns a different, managed object	Tracing One Entity Through the JPA Lifecycle
With `IDENTITY` ids, `persist()` inserts at once; with `SEQUENCE`, at flush	When persist() Inserts: IDENTITY vs SEQUENCE Ids
Changes to a detached entity are never written	Detached Entities: Changes That Never Reach the Database
`refresh()` reloads one entity; `clear()` detaches all and reads nothing	refresh() vs clear() in JPA

When a JPA change goes missing, or appears when you did not expect it, the entity's state is the first thing to check.

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