HHH-15283 - fix NPE for NamedNativeQuery + SqlResultSetMapping (columns)

Author: NathanQingyangXu

Diff for: hibernate-core/src/main/java/org/hibernate/query/results/complete/CompleteResultBuilderBasicValuedStandard.java

@@ -27,7 +27,7 @@
 /**
  * ResultBuilder for scalar results defined via:<ul>
  *     <li>JPA {@link jakarta.persistence.ColumnResult}</li>
- *     <li>`<return-scalar/>` as part of a `<resultset/>` stanza in `hbm.xml`</li>
+ *     <li>`&lt;return-scalar/&gt;` as part of a `&lt;resultset/&gt;` stanza in `hbm.xml`</li>
  * </ul>
  *
  * @author Steve Ebersole
@@ -60,7 +60,7 @@ public ResultBuilder cacheKeyInstance() {
 
 	@Override
 	public Class<?> getJavaType() {
-		return explicitJavaType.getJavaTypeClass();
+		return explicitJavaType == null ? null : explicitJavaType.getJavaTypeClass();
 	}
 
 	@Override
@@ -173,7 +173,7 @@ public boolean equals(Object o) {
 	public int hashCode() {
 		int result = explicitColumnName != null ? explicitColumnName.hashCode() : 0;
 		result = 31 * result + ( explicitType != null ? explicitType.hashCode() : 0 );
-		result = 31 * result + explicitJavaType.hashCode();
+		result = 31 * result + ( explicitJavaType != null ? explicitJavaType.hashCode() : 0 );
 		return result;
 	}
 }

Diff for: hibernate-core/src/main/java/org/hibernate/query/sql/internal/NativeQueryImpl.java

@@ -278,7 +278,7 @@ else if ( resultJavaType != null && resultJavaType != Object[].class ) {
 					throw new IllegalArgumentException( "Named query exists but its result type is not compatible" );
 				case 1:
 					final Class<?> actualResultJavaType = resultSetMapping.getResultBuilders().get( 0 ).getJavaType();
-					if ( !resultJavaType.isAssignableFrom( actualResultJavaType ) ) {
+					if ( actualResultJavaType != null && !resultJavaType.isAssignableFrom( actualResultJavaType ) ) {
 						throw buildIncompatibleException( resultJavaType, actualResultJavaType );
 					}
 					break;

Diff for: hibernate-core/src/test/java/org/hibernate/orm/test/query/resultmapping/NamedNativeQueryWithCountColumnTest.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.query.resultmapping;
+
+import org.hibernate.cfg.AvailableSettings;
+
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.orm.junit.EntityManagerFactoryScope;
+import org.hibernate.testing.orm.junit.Jpa;
+import org.hibernate.testing.orm.junit.Setting;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.ColumnResult;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.NamedNativeQuery;
+import jakarta.persistence.SqlResultSetMapping;
+
+/**
+ * @author Nathan Xu
+ */
+@Jpa(
+		annotatedClasses = NamedNativeQueryWithCountColumnTest.Sample.class,
+		properties = @Setting(name = AvailableSettings.GLOBALLY_QUOTED_IDENTIFIERS, value = "true")
+)
+@TestForIssue(jiraKey = "HHH-15070")
+class NamedNativeQueryWithCountColumnTest {
+
+	@Test
+	void testNoNullPointerExceptionThrown(EntityManagerFactoryScope scope) {
+		scope.inTransaction( em ->em.createNamedQuery( "sample.count", Long.class ) );
+	}
+
+	@SqlResultSetMapping(
+		name = "mapping",
+		columns = @ColumnResult( name = "cnt" )
+	)
+	@NamedNativeQuery(
+		name = "sample.count",
+		resultSetMapping = "mapping",
+		query = "SELECT count(*) AS cnt FROM Sample"
+	)
+	@Entity(name = "Sample")
+	static class Sample {
+
+		@Id
+		Long id;
+
+	}
+}