hibernate8-jpa4-demo/README.md

Hibernate 8 + Jakarta Persistence 4: EntityAgent demo

Runnable companion to the ankurm.com article on EntityAgent and stateless sessions. Every number in the article comes from a file in output/, and each of those files is written by a test that asserts the same numbers, so a figure that stops being true fails the build.

Versions tested

Component	Version
Hibernate ORM	8.0.0.CR1 (release candidate, 12 Nov 2026)
Jakarta Persistence API	4.0.0-M8 (milestone, resolved transitively by CR1)
JDK	Temurin 25.0.5+8
H2	2.5.252
HSQLDB (test scope, comparison runs)	2.7.4
JUnit	6.1.3
Maven	3.9.11

Hibernate 8 and Jakarta Persistence 4 are pre-release. Assertions in Demo05Test and Demo09Test are deliberately pinned to CR1 behaviour, so they fail when a later build changes it.

Run it

./scripts/run-all.sh

Layout

Path	What it shows
src/main/java/com/ankurm/agent/	Book, Publisher, Setting entities and the BookSummary record
src/test/java/com/ankurm/agent/Lab.java	boots a SessionFactory and records every prepared SQL statement
Demo01Test	same edit through EntityManager and EntityAgent
Demo02Test	get() vs find(), no first-level cache, getMultiple()
Demo03Test	lazy associations and fetch()
Demo04Test	bulk insert: persistence-context size and statements prepared
Demo05Test	lock modes on a stateless handler, H2 and HSQLDB
Demo06Test	@ExcludedFromVersioning
Demo07Test	programmatic result set mappings
Demo08Test	upsert(), delete(), duplicate-key exception
Demo09Test	the same operations on H2 and HSQLDB

Captured output

output/01-entitymanager-vs-entityagent.txt, 02-get-find-and-no-cache, 03-lazy-associations-and-fetch, 04-bulk-insert, 05-lock-modes-in-entityagent, 06-excluded-from-versioning, 07-programmatic-result-set-mapping, 08-upsert-delete-and-errors, 09-same-operations-two-databases.