clarify some logic around @GeneratedValue

hibernate-core/src/main/java/org/hibernate/boot/internal/IdGeneratorInterpreterImpl.java

@@ -95,22 +95,27 @@ public class IdGeneratorInterpreterImpl implements IdGeneratorStrategyInterprete
 				case TABLE:
 					return org.hibernate.id.enhanced.TableGenerator.class.getName();
 				case AUTO:
-					if ( "increment".equalsIgnoreCase( context.getGeneratedValueGeneratorName() ) ) {
+					if ( UUID.class.isAssignableFrom( context.getIdType() ) ) {
-						return IncrementGenerator.class.getName();
-					}
-
-					final Class<?> javaType = context.getIdType();
-					if ( UUID.class.isAssignableFrom( javaType ) ) {
 						return UUIDGenerator.class.getName();
 					}
-
+					else if ( "increment".equalsIgnoreCase( context.getGeneratedValueGeneratorName() ) ) {
-					return SequenceStyleGenerator.class.getName();
+						// special case for @GeneratedValue(name="increment")
+						// for some reason we consider there to be an implicit
+						// generator named 'increment' (doesn't seem very useful)
+						return IncrementGenerator.class.getName();
+					}
+					else {
+						return SequenceStyleGenerator.class.getName();
+					}
 				default:
-					// UNKNOWN
+					//case UUID:
+					// (use the name instead for compatibility with javax.persistence)
 					if ( "UUID".equals( generationType.name() ) ) {
 						return UUIDGenerator.class.getName();
 					}
-					throw new UnsupportedOperationException( "Unsupported generation type:" + generationType );
+					else {
+						throw new UnsupportedOperationException( "Unsupported generation type:" + generationType );
+					}
 			}
 		}
 

hibernate-core/src/main/java/org/hibernate/boot/model/IdentifierGeneratorDefinition.java

@@ -13,8 +13,10 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 
+import org.hibernate.AnnotationException;
 import org.hibernate.AssertionFailure;
 import org.hibernate.Internal;
+import org.hibernate.boot.model.IdGeneratorStrategyInterpreter.GeneratorNameDeterminationContext;
 import org.hibernate.id.IdentifierGenerator;
 
 import jakarta.persistence.GenerationType;
@@ -109,12 +111,14 @@ public class IdentifierGeneratorDefinition implements Serializable {
 				return buildTableGeneratorDefinition( name, generationInterpreter );
 			// really AUTO and IDENTITY work the same in this respect, aside from the actual strategy name
 			case IDENTITY:
-				strategyName = "identity";
+				throw new AnnotationException(
-				break;
+						"@GeneratedValue annotation specified 'strategy=IDENTITY' and 'generator'"
+								+ " but the generator name is unnecessary"
+				);
 			case AUTO:
 				strategyName = generationInterpreter.determineGeneratorName(
 						generationType,
-						new IdGeneratorStrategyInterpreter.GeneratorNameDeterminationContext() {
+						new GeneratorNameDeterminationContext() {
 							@Override
 							public Class<?> getIdType() {
 								return idType;
@@ -127,7 +131,17 @@ public class IdentifierGeneratorDefinition implements Serializable {
 				);
 				break;
 			default:
-				throw new AssertionFailure( "unknown generator type: " + generationType );
+				//case UUID:
+				// (use the name instead for compatibility with javax.persistence)
+				if ( "UUID".equals( generationType.name() ) ) {
+					throw new AnnotationException(
+							"@GeneratedValue annotation specified 'strategy=UUID' and 'generator'"
+									+ " but the generator name is unnecessary"
+					);
+				}
+				else {
+					throw new AssertionFailure( "unknown generator type: " + generationType );
+				}
 		}
 
 		return new IdentifierGeneratorDefinition(
@@ -137,7 +151,8 @@ public class IdentifierGeneratorDefinition implements Serializable {
 		);
 	}
 
-	private static IdentifierGeneratorDefinition buildTableGeneratorDefinition(String name, IdGeneratorStrategyInterpreter generationInterpreter) {
+	private static IdentifierGeneratorDefinition buildTableGeneratorDefinition(
+			String name, IdGeneratorStrategyInterpreter generationInterpreter) {
 		final Builder builder = new Builder();
 		generationInterpreter.interpretTableGenerator(
 				new TableGenerator() {
@@ -207,7 +222,8 @@ public class IdentifierGeneratorDefinition implements Serializable {
 		return builder.build();
 	}
 
-	private static IdentifierGeneratorDefinition buildSequenceGeneratorDefinition(String name, IdGeneratorStrategyInterpreter generationInterpreter) {
+	private static IdentifierGeneratorDefinition buildSequenceGeneratorDefinition(
+			String name, IdGeneratorStrategyInterpreter generationInterpreter) {
 		final Builder builder = new Builder();
 		generationInterpreter.interpretSequenceGenerator(
 				new SequenceGenerator() {

hibernate-core/src/main/java/org/hibernate/boot/model/internal/GeneratorBinder.java

@@ -142,7 +142,7 @@ public class GeneratorBinder {
 
 	private static IdentifierGeneratorDefinition makeIdentifierGeneratorDefinition(
 			String name,
-			XProperty idXProperty,
+			XProperty idProperty,
 			Map<String, IdentifierGeneratorDefinition> localGenerators,
 			MetadataBuildingContext buildingContext) {
 		if ( localGenerators != null ) {
@@ -160,7 +160,7 @@ public class GeneratorBinder {
 
 		LOG.debugf( "Could not resolve explicit IdentifierGeneratorDefinition - using implicit interpretation (%s)", name );
 
-		final GeneratedValue generatedValue = idXProperty.getAnnotation( GeneratedValue.class );
+		final GeneratedValue generatedValue = idProperty.getAnnotation( GeneratedValue.class );
 		if ( generatedValue == null ) {
 			// this should really never happen, but it's easy to protect against it...
 			return new IdentifierGeneratorDefinition( DEFAULT_ID_GEN_STRATEGY, DEFAULT_ID_GEN_STRATEGY );
@@ -171,7 +171,7 @@ public class GeneratorBinder {
 				buildingContext
 						.getBootstrapContext()
 						.getReflectionManager()
-						.toClass( idXProperty.getType() ),
+						.toClass( idProperty.getType() ),
 				generatedValue.generator(),
 				buildingContext.getBuildingOptions().getIdGenerationTypeInterpreter(),
 				interpretGenerationType( generatedValue )

hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java

@@ -40,7 +40,6 @@ import java.util.TimeZone;
 import java.util.UUID;
 import java.util.regex.Pattern;
 
-import org.hibernate.AssertionFailure;
 import org.hibernate.Incubating;
 import org.hibernate.Length;
 import org.hibernate.LockMode;
@@ -1740,35 +1739,12 @@ public abstract class Dialect implements ConversionContext, TypeContributor, Fun
 
 
 	// native identifier generation ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
+	
-	/**
-	 * The "native" id generation strategy for this dialect.
-	 * <p>
-	 * This is the id generation strategy which should be used when {@code "native"} is
-	 * specified in {@code hbm.xml}, or {@link GenerationType#AUTO} is specified by the
-	 * {@link jakarta.persistence.GeneratedValue#strategy @GeneratedValue} annotation.
-	 *
-	 * @return The native generator strategy.
-	 */
-	@Incubating
-	public GenerationType getNativeIdentifierGenerationType() {
-		switch ( getNativeIdentifierGeneratorStrategy() ) {
-			case "identity":
-				return GenerationType.IDENTITY;
-			case "sequence":
-				return GenerationType.SEQUENCE;
-			case "uuid":
-				return GenerationType.UUID;
-			default:
-				throw new AssertionFailure( "unknown native generation type" );
-		}
-	}
 	/**
 	 * The name identifying the "native" id generation strategy for this dialect.
 	 * <p>
-	 * This is the id generation strategy which should be used when {@code "native"} is
+	 * This is the name of the id generation strategy which should be used when
-	 * specified in {@code hbm.xml}, or {@link GenerationType#AUTO} is specified by the
+	 * {@code "native"} is specified in {@code hbm.xml}.
-	 * {@link jakarta.persistence.GeneratedValue#strategy @GeneratedValue} annotation.
 	 *
 	 * @return The name identifying the native generator strategy.
 	 */

hibernate-core/src/main/java/org/hibernate/dialect/DialectDelegateWrapper.java

@@ -352,12 +352,6 @@ public class DialectDelegateWrapper extends Dialect {
 		return wrapped.getLobMergeStrategy();
 	}
 
-	@Override
-	@Incubating
-	public GenerationType getNativeIdentifierGenerationType() {
-		return wrapped.getNativeIdentifierGenerationType();
-	}
-
 	@Override
 	public String getNativeIdentifierGeneratorStrategy() {
 		return wrapped.getNativeIdentifierGeneratorStrategy();

hibernate-core/src/main/java/org/hibernate/id/factory/internal/StandardIdentifierGeneratorFactory.java

@@ -36,7 +36,6 @@ import org.hibernate.id.factory.spi.GenerationTypeStrategy;
 import org.hibernate.id.factory.spi.GenerationTypeStrategyRegistration;
 import org.hibernate.id.factory.spi.GeneratorDefinitionResolver;
 import org.hibernate.id.factory.spi.StandardGenerator;
-import org.hibernate.internal.log.DeprecationLogger;
 import org.hibernate.jpa.spi.IdentifierGeneratorStrategyProvider;
 import org.hibernate.resource.beans.container.spi.BeanContainer;
 import org.hibernate.resource.beans.internal.FallbackBeanInstanceProducer;
@@ -50,6 +49,7 @@ import jakarta.persistence.GenerationType;
 
 import static org.hibernate.cfg.AvailableSettings.IDENTIFIER_GENERATOR_STRATEGY_PROVIDER;
 import static org.hibernate.id.factory.IdGenFactoryLogging.ID_GEN_FAC_LOGGER;
+import static org.hibernate.internal.log.DeprecationLogger.DEPRECATION_LOGGER;
 
 /**
  * Basic implementation of {@link org.hibernate.id.factory.IdentifierGeneratorFactory},
@@ -151,7 +151,7 @@ public class StandardIdentifierGeneratorFactory
 		final ConfigurationService configService = serviceRegistry.getService( ConfigurationService.class );
 		final Object providerSetting = configService.getSettings().get( IDENTIFIER_GENERATOR_STRATEGY_PROVIDER );
 		if ( providerSetting != null ) {
-			DeprecationLogger.DEPRECATION_LOGGER.deprecatedSetting2(
+			DEPRECATION_LOGGER.deprecatedSetting2(
 					IDENTIFIER_GENERATOR_STRATEGY_PROVIDER,
 					"supply a org.hibernate.id.factory.spi.GenerationTypeStrategyRegistration Java service"
 			);
@@ -243,32 +243,32 @@ public class StandardIdentifierGeneratorFactory
 
 	@Override
 	public Class<? extends Generator> getIdentifierGeneratorClass(String strategy) {
-		if ( "hilo".equals( strategy ) ) {
+		switch ( strategy ) {
-			throw new UnsupportedOperationException( "Support for 'hilo' generator has been removed" );
+			case "hilo":
+				throw new UnsupportedOperationException( "Support for 'hilo' generator has been removed" );
+			case "native":
+				strategy = getDialect().getNativeIdentifierGeneratorStrategy();
+				//then fall through:
+			default:
+				Class<? extends Generator> generatorClass = legacyGeneratorClassNameMap.get( strategy );
+				return generatorClass != null ? generatorClass : generatorClassForName( strategy );
 		}
-		final String resolvedStrategy = "native".equals( strategy )
+	}
-				? getDialect().getNativeIdentifierGeneratorStrategy()
-				: strategy;
 
-		Class<? extends Generator> generatorClass = legacyGeneratorClassNameMap.get( resolvedStrategy );
+	private Class<? extends Generator> generatorClassForName(String strategy) {
-		if ( generatorClass != null ) {
+		try {
-			return generatorClass;
+			Class<? extends Generator> clazz =
+					serviceRegistry.getService( ClassLoaderService.class )
+							.classForName( strategy );
+			if ( !Generator.class.isAssignableFrom( clazz ) ) {
+				// in principle, this shouldn't happen, since @GenericGenerator
+				// constrains the type to subtypes of Generator
+				throw new MappingException( clazz.getName() + " does not implement 'Generator'" );
+			}
+			return clazz;
 		}
-		else {
+		catch ( ClassLoadingException e ) {
-			try {
+			throw new MappingException( String.format( "Could not interpret id generator strategy [%s]", strategy) );
-				Class<? extends Generator> clazz =
-						serviceRegistry.getService( ClassLoaderService.class )
-								.classForName( resolvedStrategy );
-				if ( !Generator.class.isAssignableFrom( clazz ) ) {
-					// in principle, this shouldn't happen, since @GenericGenerator
-					// constrains the type to subtypes of Generator
-					throw new MappingException( clazz.getName() + " does not implement 'Generator'" );
-				}
-				return clazz;
-			}
-			catch ( ClassLoadingException e ) {
-				throw new MappingException( String.format( "Could not interpret id generator strategy [%s]", strategy ) );
-			}
 		}
 	}
 }