allow @UuidGenerator to be applied to a non-@Id field

hibernate-core/src/main/java/org/hibernate/annotations/UuidGenerator.java

@@ -13,6 +13,7 @@ import java.util.UUID;
 
 import static java.lang.annotation.ElementType.FIELD;
 import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
 /**
  * Specifies that an entity identifier is generated as an RFC 4122 UUID.
@@ -23,8 +24,9 @@ import static java.lang.annotation.ElementType.METHOD;
  *
  * @since 6.0
  */
-@IdGeneratorType( org.hibernate.id.uuid.UuidGenerator.class )
-@Retention(RetentionPolicy.RUNTIME)
+@IdGeneratorType(org.hibernate.id.uuid.UuidGenerator.class)
+@ValueGenerationType(generatedBy = org.hibernate.id.uuid.UuidGenerator.class)
+@Retention(RUNTIME)
 @Target({ FIELD, METHOD })
 public @interface UuidGenerator {
 

hibernate-core/src/main/java/org/hibernate/id/uuid/UuidGenerator.java

@@ -14,6 +14,7 @@ import org.hibernate.HibernateException;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.generator.EventType;
 import org.hibernate.generator.EventTypeSets;
+import org.hibernate.generator.GeneratorCreationContext;
 import org.hibernate.id.factory.spi.CustomIdGeneratorCreationContext;
 import org.hibernate.generator.BeforeExecutionGenerator;
 import org.hibernate.type.descriptor.java.UUIDJavaType;
@@ -36,10 +37,9 @@ public class UuidGenerator implements BeforeExecutionGenerator {
 	private final ValueGenerator generator;
 	private final ValueTransformer valueTransformer;
 
-	public UuidGenerator(
+	private UuidGenerator(
 			org.hibernate.annotations.UuidGenerator config,
-			Member idMember,
-			CustomIdGeneratorCreationContext creationContext) {
+			Member idMember) {
 		if ( config.style() == TIME ) {
 			generator = new CustomVersionOneStrategy();
 		}
@@ -63,6 +63,20 @@ public class UuidGenerator implements BeforeExecutionGenerator {
 		}
 	}
 
+	public UuidGenerator(
+			org.hibernate.annotations.UuidGenerator config,
+			Member idMember,
+			CustomIdGeneratorCreationContext creationContext) {
+		this(config, idMember);
+	}
+
+	public UuidGenerator(
+			org.hibernate.annotations.UuidGenerator config,
+			Member idMember,
+			GeneratorCreationContext creationContext) {
+		this(config, idMember);
+	}
+
 	/**
 	 * @return {@link EventTypeSets#INSERT_ONLY}
 	 */

hibernate-core/src/test/java/org/hibernate/orm/test/id/uuid/annotation/TheOtherEntity.java

@@ -0,0 +1,49 @@
+/*
+ * 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.id.uuid.annotation;
+
+import jakarta.persistence.Basic;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import org.hibernate.annotations.UuidGenerator;
+
+import java.util.UUID;
+
+@Entity(name = "TheOtherEntity")
+@Table(name = "TheOtherEntity")
+public class TheOtherEntity {
+	@Id @GeneratedValue
+	public Long pk;
+
+	@UuidGenerator
+	public UUID id;
+
+	@Basic
+	public String name;
+
+	private TheOtherEntity() {
+		// for Hibernate use
+	}
+
+	public TheOtherEntity(String name) {
+		this.name = name;
+	}
+
+	public UUID getId() {
+		return id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+}

hibernate-core/src/test/java/org/hibernate/orm/test/id/uuid/annotation/UuidGeneratorAnnotationTests.java

@@ -17,7 +17,7 @@ import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-@DomainModel( annotatedClasses = TheEntity.class )
+@DomainModel( annotatedClasses = {TheEntity.class, TheOtherEntity.class} )
 @SessionFactory
 public class UuidGeneratorAnnotationTests {
 	@Test
@@ -36,7 +36,20 @@ public class UuidGeneratorAnnotationTests {
 	@Test
 	public void basicUseTest(SessionFactoryScope scope) {
 		scope.inTransaction( (session) -> {
-			session.persist( new TheEntity( "steve" ) );
+			TheEntity steve = new TheEntity("steve");
+			session.persist( steve );
+			session.flush();
+			assertThat( steve.id ).isNotNull();
+		} );
+	}
+
+	@Test
+	public void nonPkUseTest(SessionFactoryScope scope) {
+		scope.inTransaction( (session) -> {
+			TheOtherEntity gavin = new TheOtherEntity("gavin");
+			session.persist( gavin );
+			session.flush();
+			assertThat( gavin.id ).isNotNull();
 		} );
 	}
 }