reproducer for class cast https://discourse.hibernate.org/t/cannot-be-cast-to-cl…

orm/hibernate-orm-6/src/test/java/org/hibernate/bugs/A.java

@@ -0,0 +1,32 @@
+package org.hibernate.bugs;
+
+import org.hibernate.bugs.b.B;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+
+@Entity
+@Inheritance(strategy = InheritanceType.JOINED)
+public class A {
+    @Id
+    protected long id;
+    protected String name;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

orm/hibernate-orm-6/src/test/java/org/hibernate/bugs/JPAUnitTestCase.java

@@ -13,26 +13,27 @@
  */
 class JPAUnitTestCase {
 
-	private EntityManagerFactory entityManagerFactory;
+    private EntityManagerFactory entityManagerFactory;
 
-	@BeforeEach
-	void init() {
-		entityManagerFactory = Persistence.createEntityManagerFactory( "templatePU" );
-	}
+    @BeforeEach
+    void init() {
+        entityManagerFactory = Persistence.createEntityManagerFactory("templatePU");
+    }
 
-	@AfterEach
-	void destroy() {
-		entityManagerFactory.close();
-	}
+    @AfterEach
+    void destroy() {
+        entityManagerFactory.close();
+    }
 
-	// Entities are auto-discovered, so just add them anywhere on class-path
-	// Add your tests, using standard JUnit.
-	@Test
-	void hhh123Test() throws Exception {
-		EntityManager entityManager = entityManagerFactory.createEntityManager();
-		entityManager.getTransaction().begin();
-		// Do stuff...
-		entityManager.getTransaction().commit();
-		entityManager.close();
-	}
+    // Entities are auto-discovered, so just add them anywhere on class-path
+    // Add your tests, using standard JUnit.
+    @Test
+    void hhh123Test() throws Exception {
+        EntityManager entityManager = entityManagerFactory.createEntityManager();
+        entityManager.getTransaction().begin();
+        // Do stuff...
+        A a = entityManager.find(A.class, 1L);
+        entityManager.getTransaction().commit();
+        entityManager.close();
+    }
 }

orm/hibernate-orm-6/src/test/java/org/hibernate/bugs/b/B.java

@@ -0,0 +1,31 @@
+package org.hibernate.bugs.b;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import org.hibernate.bugs.A;
+
+@Entity
+@Inheritance(strategy = InheritanceType.JOINED)
+public class B extends A{
+    @Id
+    protected long id;
+    protected String bname;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getBname() {
+        return bname;
+    }
+
+    public void setBname(String bname) {
+        this.bname = bname;
+    }
+}