BAEL-5985 Hibernate @CreationTimestamp and @UpdateTimestamp (#13690)

* BAEL-5985 Hibernate @CreationTimestamp and @UpdateTimestamp

* BAEL-5985 Remove unnecessary imports

* BAEL-5985 Swap order in assertEquals

---------

Co-authored-by: Mariusz Kaczmarczyk <to@mariu.sh>

persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/creationupdatetimestamp/model/Book.java

@@ -0,0 +1,57 @@
+package com.baeldung.hibernate.creationupdatetimestamp.model;
+
+import java.time.Instant;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.UpdateTimestamp;
+
+@Entity
+public class Book {
+    @Id
+    @GeneratedValue
+    private Long id;
+    private String title;
+    @CreationTimestamp
+    private Instant createdOn;
+    @UpdateTimestamp
+    private Instant lastUpdatedOn;
+
+    public Book() {
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public Instant getCreatedOn() {
+        return createdOn;
+    }
+
+    public void setCreatedOn(Instant createdOn) {
+        this.createdOn = createdOn;
+    }
+
+    public Instant getLastUpdatedOn() {
+        return lastUpdatedOn;
+    }
+
+    public void setLastUpdatedOn(Instant lastUpdatedOn) {
+        this.lastUpdatedOn = lastUpdatedOn;
+    }
+}

persistence-modules/hibernate-annotations/src/test/java/com/baeldung/hibernate/creationupdatetimestamp/HibernateCreationUpdateTimestampIntegrationTest.java

@@ -0,0 +1,116 @@
+package com.baeldung.hibernate.creationupdatetimestamp;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.time.Instant;
+
+import org.h2.Driver;
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.cfg.Configuration;
+import org.hibernate.dialect.H2Dialect;
+import org.hibernate.service.ServiceRegistry;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.hibernate.creationupdatetimestamp.model.Book;
+
+class HibernateCreationUpdateTimestampIntegrationTest {
+
+    private static SessionFactory sessionFactory;
+
+    private Session session;
+
+    @BeforeAll
+    public static void beforeTests() {
+        Configuration configuration = new Configuration().addAnnotatedClass(Book.class)
+          .setProperty("hibernate.dialect", H2Dialect.class.getName())
+          .setProperty("hibernate.connection.driver_class", Driver.class.getName())
+          .setProperty("hibernate.connection.url", "jdbc:h2:mem:test")
+          .setProperty("hibernate.connection.username", "sa")
+          .setProperty("hibernate.connection.password", "")
+          .setProperty("hibernate.hbm2ddl.auto", "update");
+
+        ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties())
+          .build();
+
+        sessionFactory = configuration.buildSessionFactory(serviceRegistry);
+    }
+
+    @Test
+    void whenCreatingEntity_ThenCreatedOnIsSet() {
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+        Book book = new Book();
+
+        session.save(book);
+        session.getTransaction()
+          .commit();
+        session.close();
+
+        assertNotNull(book.getCreatedOn());
+    }
+
+    @Test
+    void whenCreatingEntity_ThenCreatedOnAndLastUpdatedOnAreBothSet() {
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+        Book book = new Book();
+
+        session.save(book);
+        session.getTransaction()
+          .commit();
+        session.close();
+
+        assertNotNull(book.getCreatedOn());
+        assertNotNull(book.getLastUpdatedOn());
+    }
+
+    @Test
+    void whenCreatingEntity_ThenCreatedOnAndLastUpdatedOnAreNotEqual() {
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+        Book book = new Book();
+
+        session.save(book);
+        session.getTransaction()
+          .commit();
+        session.close();
+
+        assertNotEquals(book.getCreatedOn(), book.getLastUpdatedOn());
+    }
+
+    @Test
+    void whenUpdatingEntity_ThenLastUpdatedOnIsUpdatedAndCreatedOnStaysTheSame() {
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+        Book book = new Book();
+        session.save(book);
+        session.flush();
+        Instant createdOnAfterCreation = book.getCreatedOn();
+        Instant lastUpdatedOnAfterCreation = book.getLastUpdatedOn();
+
+        String newName = "newName";
+        book.setTitle(newName);
+        session.getTransaction()
+          .commit();
+        session.close();
+        Instant createdOnAfterUpdate = book.getCreatedOn();
+        Instant lastUpdatedOnAfterUpdate = book.getLastUpdatedOn();
+
+        assertEquals(newName, book.getTitle());
+        assertNotNull(createdOnAfterUpdate);
+        assertNotNull(lastUpdatedOnAfterUpdate);
+        assertEquals(createdOnAfterCreation, createdOnAfterUpdate);
+        assertNotEquals(lastUpdatedOnAfterCreation, lastUpdatedOnAfterUpdate);
+    }
+
+    @AfterAll
+    static void afterTests() {
+        sessionFactory.close();
+    }
+}