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/IdentityBatchTest.java

@@ -0,0 +1,47 @@
+package com.ankurm.hibernatedemo;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.ankurm.hibernatedemo.model.WidgetIdentity;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+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;
+
+/**
+ * Backs ankurm.com post 4861. Docs: docs/03-inserting-objects.md.
+ * Run with {@code ./mvnw -Dtest=IdentityBatchTest test}.
+ */
+@SpringBootTest
+class IdentityBatchTest {
+
+    private static final int ROW_COUNT = 30;
+
+    @Autowired
+    private EntityManagerFactory emf;
+
+    @Test
+    void identityGeneratorDisablesBatching_despiteBatchSizeBeingSet() {
+        SessionFactory sessionFactory = emf.unwrap(SessionFactory.class);
+        Statistics stats = sessionFactory.getStatistics();
+        stats.clear();
+
+        EntityManager em = emf.createEntityManager();
+        em.getTransaction().begin();
+        for (int i = 1; i <= ROW_COUNT; i++) {
+            em.persist(new WidgetIdentity("identity-" + i));
+        }
+        em.getTransaction().commit();
+        em.close();
+
+        assertThat(stats.getEntityInsertCount()).isEqualTo(ROW_COUNT);
+        assertThat(stats.getPrepareStatementCount())
+                .as("with GenerationType.IDENTITY, hibernate.jdbc.batch_size has nothing to batch -- "
+                        + "every insert is its own round trip because the generated key is only "
+                        + "known after the row is written")
+                .isEqualTo(ROW_COUNT);
+    }
+}