diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/CompositeIdDerivedIdWithIdClassTest.java b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/CompositeIdDerivedIdWithIdClassTest.java
new file mode 100644
index 000000000000..5bf1e7e7dd08
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/CompositeIdDerivedIdWithIdClassTest.java
@@ -0,0 +1,222 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.jpa.test.factory.puUtil;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import javax.persistence.CascadeType;
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.EntityManager;
+import javax.persistence.Id;
+import javax.persistence.IdClass;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import javax.persistence.OneToMany;
+
+import org.junit.After;
+import org.junit.Test;
+
+import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+
+import org.hibernate.testing.TestForIssue;
+
+import static org.junit.Assert.assertEquals;
+
+public class CompositeIdDerivedIdWithIdClassTest extends BaseEntityManagerFunctionalTestCase {
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class<?>[] {
+				ShoppingCart.class,
+				LineItem.class
+		};
+	}
+
+	@After
+	public void cleanup() {
+		EntityManager em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+		em.createQuery( "delete from LineItem" ).executeUpdate();
+		em.createQuery( "delete from Cart" ).executeUpdate();
+		em.getTransaction().commit();
+		em.close();
+	}
+
+	@Test
+	@TestForIssue(jiraKey = "HHH-11328")
+	public void testMergeTransientIdManyToOne() throws Exception {
+		ShoppingCart transientCart = new ShoppingCart( "cart1" );
+		transientCart.addLineItem( new LineItem( 0, "description2", transientCart ) );
+
+		// assertion for HHH-11274 - checking for exception
+		//final Object identifier = new PersistenceUnitUtilImpl( sessionFactory() ).getIdentifier( transientCart.getLineItems().get( 0 ) );
+		final Object identifier = entityManagerFactory().getPersistenceUnitUtil().getIdentifier(
+				transientCart.getLineItems()
+						.get( 0 )
+		);
+
+		// merge ID with transient many-to-one
+		EntityManager em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+		em.merge( transientCart );
+		em.getTransaction().commit();
+		em.close();
+
+		em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+		ShoppingCart updatedCart = em.find( ShoppingCart.class, "cart1" );
+		// assertion for HHH-11274 - checking for exception
+		// new PersistenceUnitUtilImpl( sessionFactory() ).getIdentifier( transientCart.getLineItems().get( 0 ) );
+		entityManagerFactory().getPersistenceUnitUtil().getIdentifier( transientCart.getLineItems().get( 0 ) );
+		assertEquals( 1, updatedCart.getLineItems().size() );
+		assertEquals( "description2", updatedCart.getLineItems().get( 0 ).getDescription() );
+		em.getTransaction().commit();
+		em.close();
+	}
+
+	@Test
+	@TestForIssue(jiraKey = "HHH-10623")
+	public void testMergeDetachedIdManyToOne() throws Exception {
+		ShoppingCart cart = new ShoppingCart("cart1");
+
+		EntityManager em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+		em.persist( cart );
+		em.getTransaction().commit();
+		em.close();
+
+		// cart is detached now
+		LineItem lineItem = new LineItem( 0, "description2", cart );
+		cart.addLineItem( lineItem );
+
+		// merge lineItem with an ID with detached many-to-one
+		em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+		em.merge(lineItem);
+		em.getTransaction().commit();
+		em.close();
+
+		em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+		ShoppingCart updatedCart = em.find( ShoppingCart.class, "cart1" );
+		assertEquals( 1, updatedCart.getLineItems().size() );
+		assertEquals("description2", updatedCart.getLineItems().get( 0 ).getDescription());
+		em.getTransaction().commit();
+		em.close();
+	}
+
+	@Entity(name = "Cart")
+	public static class ShoppingCart {
+		@Id
+		@Column(name = "id", nullable = false)
+		private String id;
+
+		@OneToMany(mappedBy = "cart", cascade = CascadeType.ALL, orphanRemoval = true)
+		private List<LineItem> lineItems = new ArrayList<>();
+
+		protected ShoppingCart() {
+		}
+
+		public ShoppingCart(String id) {
+			this.id = id;
+		}
+
+		public List<LineItem> getLineItems() {
+			return lineItems;
+		}
+
+		public void addLineItem(LineItem lineItem) {
+			lineItems.add(lineItem);
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (this == o) return true;
+			if (o == null || getClass() != o.getClass()) return false;
+			ShoppingCart that = (ShoppingCart) o;
+			return Objects.equals( id, that.id );
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash(id);
+		}
+	}
+
+	@Entity(name = "LineItem")
+	@IdClass(LineItem.Pk.class)
+	public static class LineItem {
+
+		@Id
+		@Column(name = "item_seq_number", nullable = false)
+		private Integer sequenceNumber;
+
+		@Column(name = "description")
+		private String description;
+
+		@Id
+		@ManyToOne
+		@JoinColumn(name = "cart_id")
+		private ShoppingCart cart;
+
+		protected LineItem() {
+		}
+
+		public LineItem(Integer sequenceNumber, String description, ShoppingCart cart) {
+			this.sequenceNumber = sequenceNumber;
+			this.description = description;
+			this.cart = cart;
+		}
+
+		public Integer getSequenceNumber() {
+			return sequenceNumber;
+		}
+
+		public ShoppingCart getCart() {
+			return cart;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (this == o) return true;
+			if (!(o instanceof LineItem)) return false;
+			LineItem lineItem = (LineItem) o;
+			return Objects.equals(getSequenceNumber(), lineItem.getSequenceNumber()) &&
+					Objects.equals(getCart(), lineItem.getCart());
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash( getSequenceNumber(), getCart() );
+		}
+
+		public String getDescription() {
+			return description;
+		}
+
+		public static class Pk implements Serializable {
+			public Integer sequenceNumber;
+			public String cart;
+
+			@Override
+			public boolean equals(Object o) {
+				if (this == o) return true;
+				if (!(o instanceof Pk)) return false;
+				Pk pk = (Pk) o;
+				return Objects.equals(sequenceNumber, pk.sequenceNumber) &&
+						Objects.equals(cart, pk.cart);
+			}
+
+			@Override
+			public int hashCode() {
+				return Objects.hash(sequenceNumber, cart);
+			}
+		}
+	}
+}
diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/CompositeIdDerivedIdWithIdClassTest.java.rej b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/CompositeIdDerivedIdWithIdClassTest.java.rej
new file mode 100644
index 000000000000..1331b68a5516
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/CompositeIdDerivedIdWithIdClassTest.java.rej
@@ -0,0 +1,30 @@
+--- hibernate-entitymanager/src/test/java/org/hibernate/test/annotations/derivedidentities/bidirectional/CompositeIdDerivedIdWithIdClassTest.java
++++ hibernate-entitymanager/src/test/java/org/hibernate/test/annotations/derivedidentities/bidirectional/CompositeIdDerivedIdWithIdClassTest.java
+@@ -23,6 +23,8 @@ import org.junit.After;
+ import org.junit.Test;
+ 
+ import org.hibernate.Session;
++import org.hibernate.jpa.internal.PersistenceUnitUtilImpl;
++
+ import org.hibernate.testing.TestForIssue;
+ import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+ 
+@@ -53,6 +55,9 @@ public class CompositeIdDerivedIdWithIdClassTest extends BaseCoreFunctionalTestC
+ 		ShoppingCart transientCart = new ShoppingCart( "cart1" );
+ 		transientCart.addLineItem( new LineItem( 0, "description2", transientCart ) );
+ 
++		// assertion for HHH-11274 - checking for exception
++		final Object identifier = new PersistenceUnitUtilImpl( sessionFactory() ).getIdentifier( transientCart.getLineItems().get( 0 ) );
++
+ 		// merge ID with transient many-to-one
+ 		Session s = openSession();
+ 		s.getTransaction().begin();
+@@ -63,6 +68,8 @@ public class CompositeIdDerivedIdWithIdClassTest extends BaseCoreFunctionalTestC
+ 		s = openSession();
+ 		s.getTransaction().begin();
+ 		ShoppingCart updatedCart = s.get( ShoppingCart.class, "cart1" );
++		// assertion for HHH-11274 - checking for exception
++		new PersistenceUnitUtilImpl( sessionFactory() ).getIdentifier( transientCart.getLineItems().get( 0 ) );
+ 		assertEquals( 1, updatedCart.getLineItems().size() );
+ 		assertEquals( "description2", updatedCart.getLineItems().get( 0 ).getDescription() );
+ 		s.getTransaction().commit();
diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/GetIdentifierTest.java b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/GetIdentifierTest.java
new file mode 100644
index 000000000000..b2a06b8003f9
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/GetIdentifierTest.java
@@ -0,0 +1,70 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.jpa.test.factory.puUtil;
+
+import java.io.Serializable;
+import javax.persistence.EntityManager;
+
+import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * @author Steve Ebersole
+ */
+public class GetIdentifierTest extends BaseEntityManagerFunctionalTestCase {
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class[] {
+				LegacyEntity.class,
+				ModernEntity.class,
+				NestedLegacyEntity.class
+		};
+	}
+
+	@Before
+	public void createData() {
+
+	}
+
+	@After
+	public void dropData() {
+
+	}
+
+	@Test
+	public void getIdentifierTest() throws Exception {
+		EntityManager entityManager = getOrCreateEntityManager();
+		entityManager.getTransaction().begin();
+
+		// This gives a NullPointerException right now. Look at HHH-10623 when this issue is fixed
+		Serializable nestedLegacyEntityId = (Serializable) entityManager.getEntityManagerFactory()
+				.getPersistenceUnitUtil().getIdentifier(createExisitingNestedLegacyEntity());
+
+		entityManager.getTransaction().commit();
+		entityManager.close();
+	}
+
+	private NestedLegacyEntity createExisitingNestedLegacyEntity() {
+
+		ModernEntity modernEntity = new ModernEntity();
+		modernEntity.setFoo(2);
+
+		LegacyEntity legacyEntity = new LegacyEntity();
+		legacyEntity.setPrimitivePk1(1);
+		legacyEntity.setPrimitivePk2(2);
+		legacyEntity.setFoo("Foo");
+
+		NestedLegacyEntity nestedLegacyEntity = new NestedLegacyEntity();
+		nestedLegacyEntity.setModernEntity(modernEntity);
+		nestedLegacyEntity.setLegacyEntity(legacyEntity);
+
+		return nestedLegacyEntity;
+	}
+}
diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/LegacyEntity.java b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/LegacyEntity.java
new file mode 100644
index 000000000000..06f302e9a994
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/LegacyEntity.java
@@ -0,0 +1,77 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.jpa.test.factory.puUtil;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.IdClass;
+
+@Entity(name = "LegacyEntity")
+@IdClass(LegacyEntityPk.class)
+public class LegacyEntity {
+
+    @Id
+    private int primitivePk1;
+
+    @Id
+    private int primitivePk2;
+
+    private String foo;
+
+    public LegacyEntity() {}
+
+    public int getPrimitivePk1() {
+        return primitivePk1;
+    }
+
+    public void setPrimitivePk1(int primitivePk1) {
+        this.primitivePk1 = primitivePk1;
+    }
+
+    public int getPrimitivePk2() {
+        return primitivePk2;
+    }
+
+    public void setPrimitivePk2(int primitivePk2) {
+        this.primitivePk2 = primitivePk2;
+    }
+
+    public String getFoo() {
+        return foo;
+    }
+
+    public void setFoo(String foo) {
+        this.foo = foo;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        LegacyEntity that = (LegacyEntity) o;
+
+        if (primitivePk1 != that.primitivePk1) return false;
+        return primitivePk2 == that.primitivePk2;
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = primitivePk1;
+        result = 31 * result + primitivePk2;
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "LegacyEntity{" +
+                "primitivePk1=" + primitivePk1 +
+                ", primitivePk2=" + primitivePk2 +
+                '}';
+    }
+}
diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/LegacyEntityPk.java b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/LegacyEntityPk.java
new file mode 100644
index 000000000000..f3307fc5896c
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/LegacyEntityPk.java
@@ -0,0 +1,54 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.jpa.test.factory.puUtil;
+
+import java.io.Serializable;
+
+public class LegacyEntityPk implements Serializable {
+
+    private int primitivePk1;
+
+    private int primitivePk2;
+
+    public LegacyEntityPk() {
+    }
+
+    public int getPrimitivePk1() {
+        return primitivePk1;
+    }
+
+    public void setPrimitivePk1(int primitivePk1) {
+        this.primitivePk1 = primitivePk1;
+    }
+
+    public int getPrimitivePk2() {
+        return primitivePk2;
+    }
+
+    public void setPrimitivePk2(int primitivePk2) {
+        this.primitivePk2 = primitivePk2;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        LegacyEntityPk that = (LegacyEntityPk) o;
+
+        if (primitivePk1 != that.primitivePk1) return false;
+        return primitivePk2 == that.primitivePk2;
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = primitivePk1;
+        result = 31 * result + primitivePk2;
+        return result;
+    }
+}
diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/ModernEntity.java b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/ModernEntity.java
new file mode 100644
index 000000000000..2da6f5b42935
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/ModernEntity.java
@@ -0,0 +1,63 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.jpa.test.factory.puUtil;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+@Entity(name = "ModernEntity")
+public class ModernEntity {
+
+    @Id
+    @GeneratedValue
+    private int id;
+
+    private int foo;
+
+    public ModernEntity() {
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public int getFoo() {
+        return foo;
+    }
+
+    public void setFoo(int foo) {
+        this.foo = foo;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        ModernEntity that = (ModernEntity) o;
+
+        return id == that.id;
+
+    }
+
+    @Override
+    public int hashCode() {
+        return id;
+    }
+
+    @Override
+    public String toString() {
+        return "ModernEntity{" +
+                "id=" + id +
+                '}';
+    }
+}
diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/NestedLegacyEntity.java b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/NestedLegacyEntity.java
new file mode 100644
index 000000000000..977c83266ad6
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/NestedLegacyEntity.java
@@ -0,0 +1,76 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.jpa.test.factory.puUtil;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.IdClass;
+import javax.persistence.JoinColumn;
+import javax.persistence.JoinColumns;
+import javax.persistence.ManyToOne;
+
+@Entity(name = "NestedLegacyEntity")
+@IdClass(NestedLegacyEntityPk.class)
+public class NestedLegacyEntity {
+
+    @Id
+    @ManyToOne
+    @JoinColumns({@JoinColumn(name = "legacyFk1", referencedColumnName = "primitivePk1"),
+            @JoinColumn(name = "legacyFk2", referencedColumnName = "primitivePk2")})
+    private LegacyEntity legacyEntity;
+
+    @Id
+    @ManyToOne
+    @JoinColumn(name = "modernFk", referencedColumnName = "id")
+    private ModernEntity modernEntity;
+
+    public NestedLegacyEntity() {
+    }
+
+    public LegacyEntity getLegacyEntity() {
+        return legacyEntity;
+    }
+
+    public void setLegacyEntity(LegacyEntity legacyEntity) {
+        this.legacyEntity = legacyEntity;
+    }
+
+    public ModernEntity getModernEntity() {
+        return modernEntity;
+    }
+
+    public void setModernEntity(ModernEntity modernEntity) {
+        this.modernEntity = modernEntity;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        NestedLegacyEntity that = (NestedLegacyEntity) o;
+
+        if (legacyEntity != null ? !legacyEntity.equals(that.legacyEntity) : that.legacyEntity != null) return false;
+        return modernEntity != null ? modernEntity.equals(that.modernEntity) : that.modernEntity == null;
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = legacyEntity != null ? legacyEntity.hashCode() : 0;
+        result = 31 * result + (modernEntity != null ? modernEntity.hashCode() : 0);
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "NestedLegacyEntity{" +
+                "legacyEntity=" + legacyEntity +
+                ", modernEntity=" + modernEntity +
+                '}';
+    }
+}
diff --git a/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/NestedLegacyEntityPk.java b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/NestedLegacyEntityPk.java
new file mode 100644
index 000000000000..b6afbbe1de7c
--- /dev/null
+++ b/hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/factory/puUtil/NestedLegacyEntityPk.java
@@ -0,0 +1,54 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.jpa.test.factory.puUtil;
+
+import java.io.Serializable;
+
+public class NestedLegacyEntityPk implements Serializable {
+
+    private LegacyEntityPk legacyEntity;
+
+    private int modernEntity;
+
+    public NestedLegacyEntityPk() {
+    }
+
+    public LegacyEntityPk getLegacyEntity() {
+        return legacyEntity;
+    }
+
+    public void setLegacyEntity(LegacyEntityPk legacyEntity) {
+        this.legacyEntity = legacyEntity;
+    }
+
+    public int getModernEntity() {
+        return modernEntity;
+    }
+
+    public void setModernEntity(int modernEntity) {
+        this.modernEntity = modernEntity;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        NestedLegacyEntityPk that = (NestedLegacyEntityPk) o;
+
+        if (modernEntity != that.modernEntity) return false;
+        return legacyEntity != null ? legacyEntity.equals(that.legacyEntity) : that.legacyEntity == null;
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = legacyEntity != null ? legacyEntity.hashCode() : 0;
+        result = 31 * result + modernEntity;
+        return result;
+    }
+}