HHH-9456 Test null value in element collection

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/collectionelement/NullInElementCollectionTest.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.orm.test.annotations.collectionelement;
+
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@DomainModel(
+		annotatedClasses = {
+				NullInElementCollectionTest.Holder.class,
+		}
+)
+@SessionFactory
+@Jira("https://hibernate.atlassian.net/browse/HHH-9456")
+public class NullInElementCollectionTest {
+
+	@Test
+	public void test(SessionFactoryScope scope) {
+		scope.inTransaction( s -> {
+			Holder h = new Holder();
+			h.id = 1L;
+			h.name = "A";
+			h.data.put( "a", null );
+			s.persist( h );
+			s.flush();
+			s.clear();
+
+			h = s.find( Holder.class, 1L );
+			Assertions.assertEquals( 1, h.data.size() );
+		} );
+	}
+	@Entity(name = "Holder")
+	public static class Holder {
+		@Id
+		private Long id;
+		private String name;
+		@ElementCollection
+		private Map<String, String> data = new HashMap<>();
+	}
+}