Four States, One Object

new Employee("Alex") produces an object. Nothing about the database knows it exists yet, and setting a field on it is exactly as inert as setting a field on any other plain object — nothing is being tracked, nothing will be written anywhere.

A JPA entity is always in exactly one of four states, and which one decides whether touching it does anything at all.

The four entity states
State	Means
Transient	Just an object — `new`, never persisted, not tracked
Managed (persistent)	The persistence context is tracking it; changes are picked up automatically
Detached	Was managed once; the persistence context has stopped watching it
Removed	Marked for deletion; the row disappears when the transaction commits

The four entity states and the operations that move between them

So the question that actually matters is never "is this saved?" — it's "which of the four states is this object in right now?" The rest of this topic is the operations named on the diagram, and what each one actually does.