Add Hibernate 7 batches 2-6: mapping styles, JPA annotations, natural IDs, @Immutable, stored procedures, in-memory test databases, JNDI mocking, proxies, associations, temporal mapping, named queries, HQL, Criteria API and EntityManager bootstrapping (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/main/java/com/ankurm/hibernatedemo/naturalid/NaturalIdEqualsEntity.java

@@ -0,0 +1,62 @@
+package com.ankurm.hibernatedemo.naturalid;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import java.util.Objects;
+import org.hibernate.Hibernate;
+import org.hibernate.annotations.NaturalId;
+
+/**
+ * equals()/hashCode() based on the IMMUTABLE natural id (sku), assigned in the constructor --
+ * exactly the pattern posts 4864/4865 recommend. Since sku is set before the object ever enters
+ * a Set/Map (unlike a surrogate id, which is null until flush), the hash code should be STABLE
+ * across persist(). This entity exists to test whether that advice actually holds up.
+ *
+ * <p>Docs: docs/06-natural-ids.md, Topic 3.
+ */
+@Entity
+public class NaturalIdEqualsEntity {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    @NaturalId
+    @Column(nullable = false, unique = true, updatable = false)
+    private final String sku;
+
+    private String name;
+
+    protected NaturalIdEqualsEntity() {
+        this.sku = null; // JPA no-arg constructor requirement
+    }
+
+    public NaturalIdEqualsEntity(String sku, String name) {
+        this.sku = sku;
+        this.name = name;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getSku() {
+        return sku;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null) return false;
+        if (Hibernate.getClass(this) != Hibernate.getClass(o)) return false;
+        NaturalIdEqualsEntity that = (NaturalIdEqualsEntity) o;
+        return Objects.equals(sku, that.sku);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(sku);
+    }
+}