Add Hibernate 7 batches 2-6 and batch 7: 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, and Hibernate Validator CDI integration (Hibernate 7.4.5.Final + Spring Boot 4.1.1 + JDK 25)

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EQNA6DJ9VgCtW6zhCE8Xud

src/test/java/com/ankurm/hibernatedemo/testdb/StartupTimingTest.java

@@ -0,0 +1,38 @@
+package com.ankurm.hibernatedemo.testdb;
+
+import org.hibernate.SessionFactory;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Backs docs/09-testing-in-memory-databases.md, chapter "Startup time, with the caveat this is a shared
+ * container". NOT a benchmark -- three runs per database, plain {@code System.nanoTime()},
+ * one shared, likely-noisy sandbox container. The numbers are indicative of relative order of
+ * magnitude only, and the docs/output file this writes says so explicitly.
+ */
+class StartupTimingTest {
+
+    private static final Logger DEMO = LoggerFactory.getLogger("DEMO");
+
+    private long timeOneBuild(TestDbSupport.Db db, String suffix) {
+        long start = System.nanoTime();
+        SessionFactory sf = TestDbSupport.buildSessionFactory(db, suffix, "create-drop", TestDbWidget.class);
+        long elapsedMs = (System.nanoTime() - start) / 1_000_000;
+        sf.close();
+        return elapsedMs;
+    }
+
+    @Test
+    void measureStartupAcrossThreeRunsPerDatabase() {
+        TestDbSupport.Db[] dbs = {TestDbSupport.Db.H2, TestDbSupport.Db.HSQLDB, TestDbSupport.Db.DERBY};
+        for (TestDbSupport.Db db : dbs) {
+            long[] times = new long[3];
+            for (int i = 0; i < 3; i++) {
+                times[i] = timeOneBuild(db, "timing" + i);
+            }
+            DEMO.info("startup ms for {} over 3 runs: {}, {}, {} (sandbox container -- indicative only, not a benchmark)",
+                    db, times[0], times[1], times[2]);
+        }
+    }
+}