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/MutableNaturalIdEntity.java

@@ -0,0 +1,42 @@
+package com.ankurm.hibernatedemo.naturalid;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import org.hibernate.annotations.NaturalId;
+
+/**
+ * {@code @NaturalId(mutable = true)} -- the explicit opt-in for a natural id that IS allowed
+ * to change (e.g. an email address).
+ *
+ * <p>Docs: docs/06-natural-ids.md, Topic 3.
+ */
+@Entity
+public class MutableNaturalIdEntity {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    @NaturalId(mutable = true)
+    private String code;
+
+    public MutableNaturalIdEntity() {
+    }
+
+    public MutableNaturalIdEntity(String code) {
+        this.code = code;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+    public void setCode(String code) {
+        this.code = code;
+    }
+}