Add Hibernate 7 batches 2-6, batch 7, and batch 8: mapping styles, JPA annotations, natural IDs, @Immutable, stored procedures, in-memory test databases, JNDI mocking, proxies, associations, temporal mapping, named queries, HQL, Criteria API, EntityManager bootstrapping, Ehcache 3 L2 cache configuration, HikariCP connection pooling, Hibernate Validator CDI integration, aggregate functions, sorting, pagination, interceptors, and Hibernate Search 8 (Hibernate 7.4.5.Final + Spring Boot 4.1.1 + JDK 25)

src/test/java/com/ankurm/hibernatedemo/naturalid/NaturalIdL1CacheTest.java

@@ -0,0 +1,92 @@
+package com.ankurm.hibernatedemo.naturalid;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.ankurm.hibernatedemo.HibernateDemoApplication;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.hibernate.stat.Statistics;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+/**
+ * THE central empirical question for post 4865: with NO second-level cache, does a
+ * bySimpleNaturalId lookup save a query on a second call in the SAME session? Counted with
+ * real Hibernate Statistics, not asserted from documentation.
+ *
+ * <p>Docs: docs/06-natural-ids.md, Topic 3.
+ */
+@SpringBootTest(classes = HibernateDemoApplication.class)
+class NaturalIdL1CacheTest {
+
+    @Autowired
+    private EntityManagerFactory emf;
+
+    private Statistics stats() {
+        return emf.unwrap(SessionFactory.class).getStatistics();
+    }
+
+    @Test
+    void bySimpleNaturalId_secondCallSameSession_noL2Cache_savesTheQuery() {
+        EntityManager seedEm = emf.createEntityManager();
+        seedEm.getTransaction().begin();
+        seedEm.persist(new NaturalIdProduct("SKU-L1-1", "Widget"));
+        seedEm.getTransaction().commit();
+        seedEm.close();
+
+        EntityManager em = emf.createEntityManager();
+        Session session = em.unwrap(Session.class);
+        stats().clear();
+
+        NaturalIdProduct first = session.bySimpleNaturalId(NaturalIdProduct.class).load("SKU-L1-1");
+        long queriesAfterFirst = stats().getPrepareStatementCount();
+
+        NaturalIdProduct second = session.bySimpleNaturalId(NaturalIdProduct.class).load("SKU-L1-1");
+        long queriesAfterSecond = stats().getPrepareStatementCount();
+
+        em.close();
+
+        System.out.println("RESULT[naturalid-l1-no-l2]: queries after 1st bySimpleNaturalId=" + queriesAfterFirst
+                + ", after 2nd (same session)=" + queriesAfterSecond
+                + " (no @NaturalIdCache, no L2 cache provider configured)");
+
+        assertThat(queriesAfterFirst).isEqualTo(1);
+        assertThat(queriesAfterSecond)
+                .as("second bySimpleNaturalId call in the SAME session must NOT re-fire a query -- L1 natural-id resolution cache")
+                .isEqualTo(1);
+        assertThat(second).isSameAs(first);
+    }
+
+    @Test
+    void bySimpleNaturalId_newSession_noL2Cache_reFiresTheQuery() {
+        EntityManager seedEm = emf.createEntityManager();
+        seedEm.getTransaction().begin();
+        seedEm.persist(new NaturalIdProduct("SKU-L1-2", "Gadget"));
+        seedEm.getTransaction().commit();
+        seedEm.close();
+
+        EntityManager em1 = emf.createEntityManager();
+        Session session1 = em1.unwrap(Session.class);
+        stats().clear();
+        session1.bySimpleNaturalId(NaturalIdProduct.class).load("SKU-L1-2");
+        long queriesSession1 = stats().getPrepareStatementCount();
+        em1.close();
+
+        EntityManager em2 = emf.createEntityManager();
+        Session session2 = em2.unwrap(Session.class);
+        session2.bySimpleNaturalId(NaturalIdProduct.class).load("SKU-L1-2");
+        long queriesAfterSession2 = stats().getPrepareStatementCount();
+        em2.close();
+
+        System.out.println("RESULT[naturalid-cross-session-no-l2]: queries after session 1 lookup=" + queriesSession1
+                + ", cumulative after a NEW session repeats the same lookup=" + queriesAfterSession2
+                + " (no L2 cache -- the L1 natural-id map dies with the session)");
+
+        assertThat(queriesAfterSession2)
+                .as("without L2 cache, a brand-new session must re-fire the query -- the L1 mapping does not survive session close")
+                .isEqualTo(queriesSession1 + 1);
+    }
+}