get rid of the last iterators in the mapping package

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

@@ -1872,16 +1872,14 @@ public class InFlightMetadataCollectorImpl implements InFlightMetadataCollector
 			final MetadataBuildingContext buildingContext) throws MappingException {
 		table.createForeignKeys();
 
-		Iterator itr = table.getForeignKeyIterator();
+		for ( ForeignKey foreignKey : table.getForeignKeys().values() ) {
-		while ( itr.hasNext() ) {
+			if ( !done.contains( foreignKey ) ) {
-			final ForeignKey fk = (ForeignKey) itr.next();
+				done.add( foreignKey );
-			if ( !done.contains( fk ) ) {
+				final String referencedEntityName = foreignKey.getReferencedEntityName();
-				done.add( fk );
-				final String referencedEntityName = fk.getReferencedEntityName();
 				if ( referencedEntityName == null ) {
 					throw new MappingException(
 							"An association from the table " +
-									fk.getTable().getName() +
+									foreignKey.getTable().getName() +
 									" does not specify the referenced entity"
 					);
 				}
@@ -1891,7 +1889,7 @@ public class InFlightMetadataCollectorImpl implements InFlightMetadataCollector
 				if ( referencedClass == null ) {
 					throw new MappingException(
 							"An association from the table " +
-									fk.getTable().getName() +
+									foreignKey.getTable().getName() +
 									" refers to an unmapped class: " +
 									referencedEntityName
 					);
@@ -1900,12 +1898,12 @@ public class InFlightMetadataCollectorImpl implements InFlightMetadataCollector
 					secondPassCompileForeignKeys( referencedClass.getSuperclass().getTable(), done, buildingContext );
 				}
 
-				fk.setReferencedTable( referencedClass.getTable() );
+				foreignKey.setReferencedTable( referencedClass.getTable() );
 
 				Identifier nameIdentifier;
 
 				ImplicitForeignKeyNameSource foreignKeyNameSource = new ImplicitForeignKeyNameSource() {
-					final List<Identifier> columnNames = extractColumnNames( fk.getColumns() );
+					final List<Identifier> columnNames = extractColumnNames( foreignKey.getColumns() );
 					List<Identifier> referencedColumnNames = null;
 
 					@Override
@@ -1920,20 +1918,20 @@ public class InFlightMetadataCollectorImpl implements InFlightMetadataCollector
 
 					@Override
 					public Identifier getReferencedTableName() {
-						return fk.getReferencedTable().getNameIdentifier();
+						return foreignKey.getReferencedTable().getNameIdentifier();
 					}
 
 					@Override
 					public List<Identifier> getReferencedColumnNames() {
 						if ( referencedColumnNames == null ) {
-							referencedColumnNames = extractColumnNames( fk.getReferencedColumns() );
+							referencedColumnNames = extractColumnNames( foreignKey.getReferencedColumns() );
 						}
 						return referencedColumnNames;
 					}
 
 					@Override
 					public Identifier getUserProvidedIdentifier() {
-						return fk.getName() != null ? Identifier.toIdentifier( fk.getName() ) : null;
+						return foreignKey.getName() != null ? Identifier.toIdentifier( foreignKey.getName() ) : null;
 					}
 
 					@Override
@@ -1944,9 +1942,9 @@ public class InFlightMetadataCollectorImpl implements InFlightMetadataCollector
 
 				nameIdentifier = getMetadataBuildingOptions().getImplicitNamingStrategy().determineForeignKeyName(foreignKeyNameSource);
 
-				fk.setName( nameIdentifier.render( getDatabase().getJdbcEnvironment().getDialect() ) );
+				foreignKey.setName( nameIdentifier.render( getDatabase().getJdbcEnvironment().getDialect() ) );
 
-				fk.alignColumns();
+				foreignKey.alignColumns();
 			}
 		}
 	}

hibernate-core/src/main/java/org/hibernate/boot/model/source/internal/hbm/ModelBinder.java

@@ -1814,19 +1814,19 @@ public class ModelBinder {
 			secondaryTableJoin.createForeignKey();
 		}
 	}
-
+//
-	private List<ColumnSource> sortColumns(List<ColumnSource> primaryKeyColumnSources, KeyValue identifier) {
+//	private List<ColumnSource> sortColumns(List<ColumnSource> primaryKeyColumnSources, KeyValue identifier) {
-		if ( primaryKeyColumnSources.size() == 1 || !identifier.getType().isComponentType() ) {
+//		if ( primaryKeyColumnSources.size() == 1 || !identifier.getType().isComponentType() ) {
-			return primaryKeyColumnSources;
+//			return primaryKeyColumnSources;
-		}
+//		}
-		final ComponentType componentType = (ComponentType) identifier.getType();
+//		final ComponentType componentType = (ComponentType) identifier.getType();
-		final List<ColumnSource> sortedColumnSource = new ArrayList<>( primaryKeyColumnSources.size() );
+//		final List<ColumnSource> sortedColumnSource = new ArrayList<>( primaryKeyColumnSources.size() );
-		final int[] originalPropertyOrder = componentType.getOriginalPropertyOrder();
+//		final int[] originalPropertyOrder = componentType.getOriginalPropertyOrder();
-		for ( int originalIndex : originalPropertyOrder ) {
+//		for ( int originalIndex : originalPropertyOrder ) {
-			sortedColumnSource.add( primaryKeyColumnSources.get( originalIndex ) );
+//			sortedColumnSource.add( primaryKeyColumnSources.get( originalIndex ) );
-		}
+//		}
-		return sortedColumnSource;
+//		return sortedColumnSource;
-	}
+//	}
 
 	private Property createEmbeddedAttribute(
 			MappingDocument sourceDocument,
@@ -3168,7 +3168,7 @@ public class ModelBinder {
 		}
 
 		@Override
-		public void doSecondPass(Map persistentClasses) throws org.hibernate.MappingException {
+		public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws org.hibernate.MappingException {
 			bindCollectionTable();
 
 			bindCollectionKey();
@@ -4108,7 +4108,7 @@ public class ModelBinder {
 		}
 
 		@Override
-		public void doSecondPass(Map persistentClasses) throws org.hibernate.MappingException {
+		public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws org.hibernate.MappingException {
 			if ( allColumnsNamed ) {
 				relationalObjectBinder.bindColumnsAndFormulas(
 						mappingDocument,
@@ -4202,7 +4202,7 @@ public class ModelBinder {
 		}
 
 		@Override
-		public void doSecondPass(Map persistentClasses) throws org.hibernate.MappingException {
+		public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws org.hibernate.MappingException {
 			if ( referencedEntityAttributeName == null ) {
 				manyToOneBinding.createForeignKey();
 			}

hibernate-core/src/main/java/org/hibernate/cache/cfg/internal/NaturalIdDataCachingConfigImpl.java

@@ -6,8 +6,6 @@
  */
 package org.hibernate.cache.cfg.internal;
 
-import java.util.Iterator;
-
 import org.hibernate.cache.cfg.spi.NaturalIdDataCachingConfig;
 import org.hibernate.cache.spi.access.AccessType;
 import org.hibernate.mapping.Property;
@@ -36,10 +34,8 @@ public class NaturalIdDataCachingConfigImpl
 	}
 
 	private boolean hasAnyMutableNaturalIdProps() {
-		final Iterator itr = rootEntityDescriptor.getDeclaredPropertyIterator();
+		for ( Property property : rootEntityDescriptor.getDeclaredProperties() ) {
-		while ( itr.hasNext() ) {
+			if ( property.isNaturalIdentifier() && property.isUpdateable() ) {
-			final Property prop = (Property) itr.next();
-			if ( prop.isNaturalIdentifier() && prop.isUpdateable() ) {
 				return true;
 			}
 		}

hibernate-core/src/main/java/org/hibernate/cfg/AnnotationBinder.java

@@ -1617,17 +1617,12 @@ public final class AnnotationBinder {
 					reflectionManager, entityClass, callbackType ) );
 		}
 
-		context.getMetadataCollector().addSecondPass( new SecondPass() {
+		context.getMetadataCollector().addSecondPass( persistentClasses -> {
-			@Override
+			for ( Property property : persistentClass.getDeclaredProperties() ) {
-			public void doSecondPass(Map persistentClasses) throws MappingException {
+				if ( property.isComposite() ) {
-				for ( @SuppressWarnings("unchecked") Iterator<Property> propertyIterator = persistentClass.getDeclaredPropertyIterator();
+					for ( CallbackType callbackType : CallbackType.values() ) {
-						propertyIterator.hasNext(); ) {
+						property.addCallbackDefinitions( CallbackDefinitionResolverLegacyImpl.resolveEmbeddableCallbacks(
-					Property property = propertyIterator.next();
+								reflectionManager, persistentClass.getMappedClass(), property, callbackType ) );
-					if ( property.isComposite() ) {
-						for ( CallbackType callbackType : CallbackType.values() ) {
-							property.addCallbackDefinitions( CallbackDefinitionResolverLegacyImpl.resolveEmbeddableCallbacks(
-									reflectionManager, persistentClass.getMappedClass(), property, callbackType ) );
-						}
 					}
 				}
 			}

hibernate-core/src/main/java/org/hibernate/cfg/CollectionSecondPass.java

@@ -16,6 +16,7 @@ import org.hibernate.internal.CoreMessageLogger;
 import org.hibernate.mapping.Collection;
 import org.hibernate.mapping.IndexedCollection;
 import org.hibernate.mapping.OneToMany;
+import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.Selectable;
 import org.hibernate.mapping.Value;
 
@@ -44,7 +45,7 @@ public abstract class CollectionSecondPass implements SecondPass {
 		this( buildingContext, collection, Collections.EMPTY_MAP );
 	}
 
-	public void doSecondPass(Map persistentClasses)
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses)
 			throws MappingException {
 		if ( LOG.isDebugEnabled() ) {
 			LOG.debugf( "Second pass for collection: %s", collection.getRole() );

hibernate-core/src/main/java/org/hibernate/cfg/CopyIdentifierComponentSecondPass.java

@@ -63,8 +63,8 @@ public class CopyIdentifierComponentSecondPass extends FkSecondPass {
 	}
 
 	@Override
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
-		PersistentClass referencedPersistentClass = (PersistentClass) persistentClasses.get( referencedEntityName );
+		PersistentClass referencedPersistentClass = persistentClasses.get( referencedEntityName );
 		// TODO better error names
 		if ( referencedPersistentClass == null ) {
 			throw new AnnotationException( "Unknown entity name: " + referencedEntityName );

hibernate-core/src/main/java/org/hibernate/cfg/CreateKeySecondPass.java

@@ -9,6 +9,7 @@ import java.util.Map;
 
 import org.hibernate.MappingException;
 import org.hibernate.mapping.JoinedSubclass;
+import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.RootClass;
 
 /**
@@ -26,7 +27,7 @@ public class CreateKeySecondPass implements SecondPass {
 		this.joinedSubClass = joinedSubClass;
 	}
 
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		if ( rootClass != null ) {
 			rootClass.createPrimaryKey();
 		}

hibernate-core/src/main/java/org/hibernate/cfg/IdGeneratorResolverSecondPass.java

@@ -12,6 +12,7 @@ import org.hibernate.MappingException;
 import org.hibernate.annotations.common.reflection.XProperty;
 import org.hibernate.boot.model.IdentifierGeneratorDefinition;
 import org.hibernate.boot.spi.MetadataBuildingContext;
+import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.SimpleValue;
 
 /**
@@ -50,7 +51,7 @@ public class IdGeneratorResolverSecondPass implements SecondPass {
 	}
 
 	@Override
-	public void doSecondPass(Map idGeneratorDefinitionMap) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> idGeneratorDefinitionMap) throws MappingException {
 		BinderHelper.makeIdGenerator( id, idXProperty, generatorType, generatorName, buildingContext, localIdentifierGeneratorDefinition );
 	}
 }

hibernate-core/src/main/java/org/hibernate/cfg/JoinedSubclassFkSecondPass.java

@@ -11,6 +11,7 @@ import org.hibernate.MappingException;
 import org.hibernate.boot.spi.MetadataBuildingContext;
 import org.hibernate.cfg.annotations.TableBinder;
 import org.hibernate.mapping.JoinedSubclass;
+import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.SimpleValue;
 
 /**
@@ -39,7 +40,7 @@ public class JoinedSubclassFkSecondPass extends FkSecondPass {
 		return true;
 	}
 
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		TableBinder.bindFk( entity.getSuperclass(), entity, columns, value, false, buildingContext );
 	}
 }

hibernate-core/src/main/java/org/hibernate/cfg/OneToOneSecondPass.java

@@ -76,7 +76,7 @@ public class OneToOneSecondPass implements SecondPass {
 	}
 
 	//TODO refactor this code, there is a lot of duplication in this method
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		OneToOne value = new OneToOne(
 				buildingContext,
 				propertyHolder.getTable(),
@@ -141,14 +141,13 @@ public class OneToOneSecondPass implements SecondPass {
 				//no column associated since its a one to one
 				propertyHolder.addProperty( prop, inferredData.getDeclaringClass() );
 			}
-			else {
+//			else {
 				//this is a many to one with Formula
-
+//			}
-			}
 		}
 		else {
 			value.setMappedByProperty( mappedBy );
-			PersistentClass otherSide = (PersistentClass) persistentClasses.get( value.getReferencedEntityName() );
+			PersistentClass otherSide = persistentClasses.get( value.getReferencedEntityName() );
 			Property otherSideProperty;
 			try {
 				if ( otherSide == null ) {

hibernate-core/src/main/java/org/hibernate/cfg/PkDrivenByDefaultMapsIdSecondPass.java

@@ -41,8 +41,8 @@ public class PkDrivenByDefaultMapsIdSecondPass extends FkSecondPass {
 	}
 
 	@Override
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
-		PersistentClass referencedEntity = (PersistentClass) persistentClasses.get( referencedEntityName );
+		PersistentClass referencedEntity = persistentClasses.get( referencedEntityName );
 		if ( referencedEntity == null ) {
 			throw new AnnotationException(
 					"Unknown entity name: " + referencedEntityName

hibernate-core/src/main/java/org/hibernate/cfg/PropertyHolderBuilder.java

@@ -5,6 +5,7 @@
  * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
  */
 package org.hibernate.cfg;
+
 import java.util.Map;
 
 import org.hibernate.annotations.common.reflection.XClass;
@@ -45,7 +46,7 @@ public final class PropertyHolderBuilder {
 	 *
 	 * @param component component to wrap
 	 * @param path	  component path
-	 * @param context
+	 *
 	 * @return PropertyHolder
 	 */
 	public static PropertyHolder buildPropertyHolder(

hibernate-core/src/main/java/org/hibernate/cfg/PropertyInferredData.java

@@ -5,6 +5,7 @@
  * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
  */
 package org.hibernate.cfg;
+
 import jakarta.persistence.Access;
 
 import org.hibernate.MappingException;

hibernate-core/src/main/java/org/hibernate/cfg/SecondaryTableSecondPass.java

@@ -5,19 +5,21 @@
  * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
  */
 package org.hibernate.cfg;
+
 import java.util.Map;
 
 import org.hibernate.MappingException;
 import org.hibernate.annotations.common.reflection.XAnnotatedElement;
 import org.hibernate.cfg.annotations.EntityBinder;
+import org.hibernate.mapping.PersistentClass;
 
 /**
  * @author Emmanuel Bernard
  */
 public class SecondaryTableSecondPass implements SecondPass {
-	private EntityBinder entityBinder;
+	private final EntityBinder entityBinder;
-	private PropertyHolder propertyHolder;
+	private final PropertyHolder propertyHolder;
-	private XAnnotatedElement annotatedClass;
+	private final XAnnotatedElement annotatedClass;
 
 	public SecondaryTableSecondPass(EntityBinder entityBinder, PropertyHolder propertyHolder, XAnnotatedElement annotatedClass) {
 		this.entityBinder = entityBinder;
@@ -25,7 +27,7 @@ public class SecondaryTableSecondPass implements SecondPass {
 		this.annotatedClass = annotatedClass;
 	}
 
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		entityBinder.finalSecondaryTableBinding( propertyHolder );
 		
 	}

hibernate-core/src/main/java/org/hibernate/cfg/SetBasicValueTypeSecondPass.java

@@ -10,18 +10,19 @@ import java.util.Map;
 
 import org.hibernate.MappingException;
 import org.hibernate.cfg.annotations.BasicValueBinder;
+import org.hibernate.mapping.PersistentClass;
 
 /**
  * @author Sharath Reddy
  */
 public class SetBasicValueTypeSecondPass implements SecondPass {
-	private final BasicValueBinder binder;
+	private final BasicValueBinder<?> binder;
 
-	public SetBasicValueTypeSecondPass(BasicValueBinder val) {
+	public SetBasicValueTypeSecondPass(BasicValueBinder<?> val) {
 		binder = val;
 	}
 
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		binder.fillSimpleValue();
 	}
 }

hibernate-core/src/main/java/org/hibernate/cfg/SimpleToOneFkSecondPass.java

@@ -7,6 +7,7 @@
 package org.hibernate.cfg;
 
 import org.hibernate.MappingException;
+import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.ToOne;
 
 /**
@@ -30,7 +31,7 @@ public class SimpleToOneFkSecondPass extends FkSecondPass {
 		return false;
 	}
 
-	public void doSecondPass(java.util.Map persistentClasses) throws MappingException {
+	public void doSecondPass(java.util.Map<String, PersistentClass> persistentClasses) throws MappingException {
 		value.createForeignKey();
 	}
 }

hibernate-core/src/main/java/org/hibernate/cfg/ToOneFkSecondPass.java

@@ -6,8 +6,6 @@
  */
 package org.hibernate.cfg;
 
-import java.util.Iterator;
-
 import org.hibernate.AnnotationException;
 import org.hibernate.AssertionFailure;
 import org.hibernate.MappingException;
@@ -88,10 +86,10 @@ public class ToOneFkSecondPass extends FkSecondPass {
 		return false;
 	}
 
-	public void doSecondPass(java.util.Map persistentClasses) throws MappingException {
+	public void doSecondPass(java.util.Map<String, PersistentClass> persistentClasses) throws MappingException {
 		if ( value instanceof ManyToOne ) {
 			ManyToOne manyToOne = (ManyToOne) value;
-			PersistentClass ref = (PersistentClass) persistentClasses.get( manyToOne.getReferencedEntityName() );
+			PersistentClass ref = persistentClasses.get( manyToOne.getReferencedEntityName() );
 			if ( ref == null ) {
 				throw new AnnotationException(
 						"@OneToOne or @ManyToOne on "

hibernate-core/src/main/java/org/hibernate/cfg/VerifyFetchProfileReferenceSecondPass.java

@@ -18,9 +18,9 @@ import org.hibernate.mapping.PersistentClass;
  * @author Hardy Ferentschik
  */
 public class VerifyFetchProfileReferenceSecondPass implements SecondPass {
-	private String fetchProfileName;
+	private final String fetchProfileName;
-	private FetchProfile.FetchOverride fetch;
+	private final FetchProfile.FetchOverride fetch;
-	private MetadataBuildingContext buildingContext;
+	private final MetadataBuildingContext buildingContext;
 
 	public VerifyFetchProfileReferenceSecondPass(
 			String fetchProfileName,
@@ -31,7 +31,7 @@ public class VerifyFetchProfileReferenceSecondPass implements SecondPass {
 		this.buildingContext = buildingContext;
 	}
 
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		org.hibernate.mapping.FetchProfile profile = buildingContext.getMetadataCollector().getFetchProfile(
 				fetchProfileName
 		);

hibernate-core/src/main/java/org/hibernate/cfg/annotations/MapBinder.java

@@ -7,7 +7,7 @@
 package org.hibernate.cfg.annotations;
 
 import java.util.HashMap;
-import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
@@ -129,7 +129,7 @@ public class MapBinder extends CollectionBinder {
 				// check if the index column has been mapped by the associated entity to a property;
 				// @MapKeyColumn only maps a column to the primary table for the one-to-many, so we only
 				// need to check "un-joined" properties.
-				if ( !propertyIteratorContainsColumn( persistentClass.getUnjoinedPropertyIterator(), column ) ) {
+				if ( !propertiesContainColumn( persistentClass.getUnjoinedProperties(), column ) ) {
 					// The index column is not mapped to an associated entity property so we can
 					// safely make the index column nullable.
 					column.setNullable( true );
@@ -138,9 +138,8 @@ public class MapBinder extends CollectionBinder {
 		}
 	}
 
-	private boolean propertyIteratorContainsColumn(Iterator<Property> propertyIterator, Column column) {
+	private boolean propertiesContainColumn(List<Property> properties, Column column) {
-		for (; propertyIterator.hasNext(); ) {
+		for ( Property property : properties ) {
-			final Property property = propertyIterator.next();
 			for ( Selectable selectable: property.getSelectables() ) {
 				if ( column.equals( selectable ) ) {
 					final Column iteratedColumn = (Column) selectable;

hibernate-core/src/main/java/org/hibernate/cfg/annotations/ResultsetMappingSecondPass.java

@@ -6,29 +6,20 @@
  */
 package org.hibernate.cfg.annotations;
 
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.List;
 import java.util.Map;
 import jakarta.persistence.SqlResultSetMapping;
 
 import org.hibernate.MappingException;
 import org.hibernate.boot.spi.MetadataBuildingContext;
 import org.hibernate.cfg.QuerySecondPass;
-import org.hibernate.internal.CoreLogging;
-import org.hibernate.internal.CoreMessageLogger;
-import org.hibernate.mapping.Component;
 import org.hibernate.mapping.PersistentClass;
-import org.hibernate.mapping.Property;
-import org.hibernate.mapping.ToOne;
-import org.hibernate.mapping.Value;
 import org.hibernate.boot.query.SqlResultSetMappingDescriptor;
 
 /**
  * @author Emmanuel Bernard
  */
 public class ResultsetMappingSecondPass implements QuerySecondPass {
-	private static final CoreMessageLogger LOG = CoreLogging.messageLogger( ResultsetMappingSecondPass.class );
+//	private static final CoreMessageLogger LOG = CoreLogging.messageLogger( ResultsetMappingSecondPass.class );
 
 	private final SqlResultSetMapping ann;
 	private final MetadataBuildingContext context;
@@ -41,7 +32,7 @@ public class ResultsetMappingSecondPass implements QuerySecondPass {
 	}
 
 	@Override
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		if ( ann == null ) {
 			return;
 		}
@@ -196,26 +187,26 @@ public class ResultsetMappingSecondPass implements QuerySecondPass {
 //			context.getMetadataCollector().addResultSetMapping( definition );
 //		}
 	}
-
+//
-	private String normalizeColumnQuoting(String name) {
+//	private String normalizeColumnQuoting(String name) {
-		return context.getMetadataCollector().getDatabase().toIdentifier( name ).render();
+//		return context.getMetadataCollector().getDatabase().toIdentifier( name ).render();
-	}
+//	}
-
+//
-	private List<String> getFollowers(Iterator parentPropIter, String reducedName, String name) {
+//	private List<String> getFollowers(Iterator<Property> parentPropIter, String reducedName, String name) {
-		boolean hasFollowers = false;
+//		boolean hasFollowers = false;
-		List<String> followers = new ArrayList<>();
+//		List<String> followers = new ArrayList<>();
-		while ( parentPropIter.hasNext() ) {
+//		while ( parentPropIter.hasNext() ) {
-			String currentPropertyName = ( (Property) parentPropIter.next() ).getName();
+//			String currentPropertyName = parentPropIter.next().getName();
-			String currentName = reducedName + '.' + currentPropertyName;
+//			String currentName = reducedName + '.' + currentPropertyName;
-			if ( hasFollowers ) {
+//			if ( hasFollowers ) {
-				followers.add( currentName );
+//				followers.add( currentName );
-			}
+//			}
-			if ( name.equals( currentName ) ) {
+//			if ( name.equals( currentName ) ) {
-				hasFollowers = true;
+//				hasFollowers = true;
-			}
+//			}
-		}
+//		}
-		return followers;
+//		return followers;
-	}
+//	}
 //
 //	private Iterator getSubPropertyIterator(PersistentClass pc, String reducedName) {
 //		Value value = pc.getRecursiveProperty( reducedName ).getValue();

hibernate-core/src/main/java/org/hibernate/cfg/internal/NullableDiscriminatorColumnSecondPass.java

@@ -24,9 +24,8 @@ public class NullableDiscriminatorColumnSecondPass implements SecondPass {
 	}
 
 	@Override
-	@SuppressWarnings("rawtypes")
+	public void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
-	public void doSecondPass(Map persistentClasses) throws MappingException {
+		PersistentClass rootPersistenceClass = persistentClasses.get( rootEntityName );
-		PersistentClass rootPersistenceClass = (PersistentClass) persistentClasses.get( rootEntityName );
 		if ( hasNullDiscriminatorValue( rootPersistenceClass ) ) {
 			for ( Selectable selectable: rootPersistenceClass.getDiscriminator().getSelectables() ) {
 				if ( selectable instanceof Column ) {
@@ -40,9 +39,8 @@ public class NullableDiscriminatorColumnSecondPass implements SecondPass {
 		if ( rootPersistenceClass.isDiscriminatorValueNull() ) {
 			return true;
 		}
-		Iterator<Subclass> subclassIterator = rootPersistenceClass.getSubclassIterator();
+		for ( Subclass subclass : rootPersistenceClass.getSubclasses() ) {
-		while ( subclassIterator.hasNext() ) {
+			if ( subclass.isDiscriminatorValueNull() ) {
-			if ( subclassIterator.next().isDiscriminatorValueNull() ) {
 				return true;
 			}
 		}

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

@@ -56,10 +56,7 @@ class SpannerDialectTableExporter implements Exporter<Table> {
 		}
 		else if ( table.getForeignKeys().size() > 0 ) {
 			// a table with no PK's but has FK's; often corresponds to element collection properties
-			keyColumns = new ArrayList<>();
+			keyColumns = table.getColumns();
-			for (Iterator<Column> column = table.getColumnIterator(); column.hasNext();) {
-				keyColumns.add( column.next() );
-			}
 		}
 		else {
 			// the case corresponding to a sequence-table that will only have 1 row.
@@ -77,12 +74,11 @@ class SpannerDialectTableExporter implements Exporter<Table> {
 		StringJoiner colsAndTypes = new StringJoiner( "," );
 
 
-		for (Iterator<Column> column = table.getColumnIterator(); column.hasNext();) {
+		for ( Column column : table.getColumns() ) {
-			Column col = column.next();
 			String columnDeclaration =
-					col.getName()
+					column.getName()
-							+ " " + col.getSqlType()
+							+ " " + column.getSqlType()
-							+ ( col.isNullable() ? this.spannerDialect.getNullColumnString( col.getSqlType() ) : " not null" );
+							+ ( column.isNullable() ? this.spannerDialect.getNullColumnString( column.getSqlType() ) : " not null" );
 			colsAndTypes.add( columnDeclaration );
 		}
 

hibernate-core/src/main/java/org/hibernate/dialect/unique/UniqueDelegate.java

@@ -48,10 +48,10 @@ public interface UniqueDelegate {
 	String getColumnDefinitionUniquenessFragment(Column column, SqlStringGenerationContext context);
 
 	/**
-	 * Get the fragment that can be used to apply unique constraints as part of table creation.  The implementation
+	 * Get the fragment that can be used to apply unique constraints as part of table creation.  The
-	 * should iterate over the {@link UniqueKey} instances for the given table (see
+	 * implementation should iterate over the {@link UniqueKey} instances for the given table (see
-	 * {@link org.hibernate.mapping.Table#getUniqueKeyIterator()} and generate the whole fragment for all
+	 * {@link org.hibernate.mapping.Table#getUniqueKeyIterator()} and generate the whole fragment for
-	 * unique keys
+	 * all unique keys
 	 * <p/>
 	 * Intended for Dialects which support unique constraint definitions, but just not in separate ALTER statements.
 	 *

hibernate-core/src/main/java/org/hibernate/internal/util/collections/IdentityMap.java

@@ -23,7 +23,7 @@ import java.util.function.Consumer;
 public final class IdentityMap<K,V> implements Map<K,V> {
 
 	private final LinkedHashMap<IdentityKey<K>,V> map;
-	@SuppressWarnings( {"unchecked"})
+
 	private transient Entry<IdentityKey<K>,V>[] entryArray = null;
 
 	/**

hibernate-core/src/main/java/org/hibernate/jpa/event/internal/CallbacksFactory.java

@@ -13,11 +13,9 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 
-import org.hibernate.annotations.common.reflection.ReflectionManager;
 import org.hibernate.boot.spi.SessionFactoryOptions;
 import org.hibernate.jpa.event.spi.Callback;
 import org.hibernate.jpa.event.spi.CallbackDefinition;
-import org.hibernate.jpa.event.spi.CallbackType;
 import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.Property;
 import org.hibernate.resource.beans.spi.ManagedBeanRegistry;
@@ -68,9 +66,7 @@ public final class CallbacksFactory {
 			registry.registerCallbacks( persistentClass.getMappedClass(),
 					buildCallbacks( persistentClass.getCallbackDefinitions(), beanRegistry ) );
 
-			for ( @SuppressWarnings("unchecked") Iterator<Property> propertyIterator = persistentClass.getDeclaredPropertyIterator();
+			for ( Property property : persistentClass.getDeclaredProperties() ) {
-					propertyIterator.hasNext(); ) {
-				final Property property = propertyIterator.next();
 				registry.registerCallbacks( persistentClass.getMappedClass(),
 						buildCallbacks( property.getCallbackDefinitions(), beanRegistry ) );
 			}

hibernate-core/src/main/java/org/hibernate/mapping/BasicValue.java

@@ -67,7 +67,6 @@ import static org.hibernate.mapping.MappingHelper.injectParameters;
 /**
  * @author Steve Ebersole
  */
-@SuppressWarnings({"unchecked", "rawtypes"})
 public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resolvable {
 	private static final CoreMessageLogger log = CoreLogging.messageLogger( BasicValue.class );
 
@@ -77,7 +76,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 	// incoming "configuration" values
 
 	private String explicitTypeName;
-	private Map explicitLocalTypeParams;
+	private Map<Object,Object> explicitLocalTypeParams;
 
 	private Function<TypeConfiguration, BasicJavaType> explicitJavaTypeAccess;
 	private Function<TypeConfiguration, JdbcType> explicitJdbcTypeAccess;
@@ -179,7 +178,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 	@Override
 	public long getColumnLength() {
 		final Selectable column = getColumn();
-		if ( column != null && column instanceof Column ) {
+		if ( column instanceof Column ) {
 			final Long length = ( (Column) column ).getLength();
 			return length == null ? NO_COLUMN_LENGTH : length;
 		}
@@ -191,7 +190,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 	@Override
 	public int getColumnPrecision() {
 		final Selectable column = getColumn();
-		if ( column != null && column instanceof Column ) {
+		if ( column instanceof Column ) {
 			final Integer length = ( (Column) column ).getPrecision();
 			return length == null ? NO_COLUMN_PRECISION : length;
 		}
@@ -203,7 +202,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 	@Override
 	public int getColumnScale() {
 		final Selectable column = getColumn();
-		if ( column != null && column instanceof Column ) {
+		if ( column instanceof Column ) {
 			final Integer length = ( (Column) column ).getScale();
 			return length == null ? NO_COLUMN_SCALE : length;
 		}
@@ -240,13 +239,11 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 			return;
 		}
 
-		if ( column != null ) {
+		throw new IllegalStateException(
-			throw new IllegalStateException(
+				"BasicValue [" + ownerName + "." + propertyName +
-					"BasicValue [" + ownerName + "." + propertyName +
+						"] already had column associated: `" + column.getText() +
-							"] already had column associated: `" + column.getText() +
+						"` -> `" + incomingColumn.getText() + "`"
-							"` -> `" + incomingColumn.getText() + "`"
+		);
-			);
-		}
 	}
 
 	@Override
@@ -386,12 +383,12 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 			);
 		}
 
-		JavaType jtd = null;
+		JavaType<?> jtd = null;
 
 		// determine JavaType if we can
 
 		if ( explicitJavaTypeAccess != null ) {
-			final BasicJavaType explicitJtd = explicitJavaTypeAccess.apply( typeConfiguration );
+			final BasicJavaType<?> explicitJtd = explicitJavaTypeAccess.apply( typeConfiguration );
 			if ( explicitJtd != null ) {
 				jtd = explicitJtd;
 			}
@@ -407,7 +404,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 		}
 
 		if ( jtd == null ) {
-			final JavaType reflectedJtd = determineReflectedJavaType();
+			final JavaType<?> reflectedJtd = determineReflectedJavaType();
 			if ( reflectedJtd != null ) {
 				jtd = reflectedJtd;
 			}
@@ -453,7 +450,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 
 	}
 
-	private JavaType determineReflectedJavaType() {
+	private JavaType<?> determineReflectedJavaType() {
 		final java.lang.reflect.Type impliedJavaType;
 
 		if ( resolvedJavaType != null ) {
@@ -486,8 +483,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 	}
 
 
-	@SuppressWarnings({"unchecked", "rawtypes"})
+	private static Resolution<?> interpretExplicitlyNamedType(
-	private static Resolution interpretExplicitlyNamedType(
 			String name,
 			EnumType enumerationStyle,
 			Function<TypeConfiguration, java.lang.reflect.Type> implicitJavaTypeAccess,
@@ -495,7 +491,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 			Function<TypeConfiguration, JdbcType> explicitStdAccess,
 			Function<TypeConfiguration, MutabilityPlan> explicitMutabilityPlanAccess,
 			ConverterDescriptor converterDescriptor,
-			Map localTypeParams,
+			Map<Object,Object> localTypeParams,
 			Consumer<Properties> combinedParameterConsumer,
 			JdbcTypeIndicators stdIndicators,
 			TypeConfiguration typeConfiguration,
@@ -539,7 +535,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 		if ( name.startsWith( BasicTypeImpl.EXTERNALIZED_PREFIX ) ) {
 			final BasicTypeImpl<Object> basicType = context.getBootstrapContext().resolveAdHocBasicType( name );
 
-			return new NamedBasicTypeResolution(
+			return new NamedBasicTypeResolution<>(
 					basicType.getJavaTypeDescriptor(),
 					basicType,
 					null,
@@ -549,24 +545,24 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 		}
 
 		// see if it is a named basic type
-		final BasicType basicTypeByName = typeConfiguration.getBasicTypeRegistry().getRegisteredType( name );
+		final BasicType<?> basicTypeByName = typeConfiguration.getBasicTypeRegistry().getRegisteredType( name );
 		if ( basicTypeByName != null ) {
-			final BasicValueConverter valueConverter;
+			final BasicValueConverter<?,?> valueConverter;
 			final JavaType<?> domainJtd;
 			if ( converterDescriptor != null ) {
 				valueConverter = converterDescriptor.createJpaAttributeConverter( converterCreationContext );
 				domainJtd = valueConverter.getDomainJavaType();
 			}
 			else if ( basicTypeByName instanceof ConvertedBasicType ) {
-				final ConvertedBasicType convertedType = (ConvertedBasicType) basicTypeByName;
+				final ConvertedBasicType<?> convertedType = (ConvertedBasicType<?>) basicTypeByName;
-				return new ConvertedBasicTypeResolution( convertedType, stdIndicators );
+				return new ConvertedBasicTypeResolution<>( convertedType, stdIndicators );
 			}
 			else {
 				valueConverter = null;
 				domainJtd = basicTypeByName.getJavaTypeDescriptor();
 			}
 
-			return new NamedBasicTypeResolution(
+			return new NamedBasicTypeResolution<>(
 					domainJtd,
 					basicTypeByName,
 					valueConverter,
@@ -594,7 +590,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 		// see if the name is a UserType or BasicType implementor class name
 		final ClassLoaderService cls = typeConfiguration.getServiceRegistry().getService( ClassLoaderService.class );
 		try {
-			final Class typeNamedClass = cls.classForName( name );
+			final Class<?> typeNamedClass = cls.classForName( name );
 
 			// if there are no local config params, register an implicit TypeDefinition for this custom type .
 			//  later uses may find it and re-use its cacheable reference...
@@ -670,7 +666,7 @@ public class BasicValue extends SimpleValue implements JdbcTypeIndicators, Resol
 		return typeConfiguration;
 	}
 
-	public void setExplicitTypeParams(Map explicitLocalTypeParams) {
+	public void setExplicitTypeParams(Map<Object,Object> explicitLocalTypeParams) {
 		this.explicitLocalTypeParams = explicitLocalTypeParams;
 	}
 

hibernate-core/src/main/java/org/hibernate/mapping/Constraint.java

@@ -84,7 +84,8 @@ public abstract class Constraint implements RelationalModel, Exportable, Seriali
 			if ( o instanceof Column ) {
 				defensive.add( (Column) o );
 			}
-			//else: others might be Formula instances. They don't need to be part of the name generation.
+			// else: others might be Formula instances.
+			// They don't need to be part of the name generation.
 		}
 		return generateName( prefix, table, defensive.toArray( new Column[0] ) );
 	}
@@ -156,6 +157,7 @@ public abstract class Constraint implements RelationalModel, Exportable, Seriali
 		return  columns.get( i );
 	}
 
+	@Deprecated(since = "6.0")
 	public Iterator<Column> getColumnIterator() {
 		return columns.iterator();
 	}

hibernate-core/src/main/java/org/hibernate/mapping/DenormalizedTable.java

@@ -60,19 +60,17 @@ public class DenormalizedTable extends Table {
 	@Override
 	public void createForeignKeys() {
 		includedTable.createForeignKeys();
-		Iterator<ForeignKey> iter = includedTable.getForeignKeyIterator();
+		for ( ForeignKey foreignKey : includedTable.getForeignKeys().values() ) {
-		while ( iter.hasNext() ) {
-			ForeignKey fk = iter.next();
 			createForeignKey(
 					Constraint.generateName(
-							fk.generatedConstraintNamePrefix(),
+							foreignKey.generatedConstraintNamePrefix(),
 							this,
-							fk.getColumns()
+							foreignKey.getColumns()
 					),
-					fk.getColumns(),
+					foreignKey.getColumns(),
-					fk.getReferencedEntityName(),
+					foreignKey.getReferencedEntityName(),
-					fk.getKeyDefinition(),
+					foreignKey.getKeyDefinition(),
-					fk.getReferencedColumns()
+					foreignKey.getReferencedColumns()
 			);
 		}
 	}
@@ -117,10 +115,8 @@ public class DenormalizedTable extends Table {
 	@Override
 	public Iterator<UniqueKey> getUniqueKeyIterator() {
 		if ( !includedTable.isPhysicalTable() ) {
-			Iterator<UniqueKey> iter = includedTable.getUniqueKeyIterator();
+			for ( UniqueKey uniqueKey : includedTable.getUniqueKeys().values() ) {
-			while ( iter.hasNext() ) {
+				createUniqueKey( uniqueKey.getColumns() );
-				UniqueKey uk = iter.next();
-				createUniqueKey( uk.getColumns() );
 			}
 		}
 		return getUniqueKeys().values().iterator();

hibernate-core/src/main/java/org/hibernate/mapping/ForeignKey.java

@@ -65,20 +65,14 @@ public class ForeignKey extends Constraint {
 		String[] columnNames = new String[getColumnSpan()];
 		String[] referencedColumnNames = new String[getColumnSpan()];
 
-		final Iterator<Column> referencedColumnItr;
+		final List<Column> referencedColumns = isReferenceToPrimaryKey()
-		if ( isReferenceToPrimaryKey() ) {
+				? referencedTable.getPrimaryKey().getColumns()
-			referencedColumnItr = referencedTable.getPrimaryKey().getColumnIterator();
+				: this.referencedColumns;
-		}
-		else {
-			referencedColumnItr = referencedColumns.iterator();
-		}
 
-		Iterator<Column> columnItr = getColumnIterator();
+		List<Column> columns = getColumns();
-		int i = 0;
+		for ( int i=0; i<referencedColumns.size() && i<columns.size(); i++ ) {
-		while ( columnItr.hasNext() ) {
+			columnNames[i] = columns.get(i).getQuotedName( dialect );
-			columnNames[i] = columnItr.next().getQuotedName( dialect );
+			referencedColumnNames[i] = referencedColumns.get(i).getQuotedName( dialect );
-			referencedColumnNames[i] = referencedColumnItr.next().getQuotedName( dialect );
-			i++;
 		}
 
 		final String result = keyDefinition != null ?
@@ -218,12 +212,11 @@ public class ForeignKey extends Constraint {
 		return referencedColumns.isEmpty();
 	}
 
-	public void addReferencedColumns(Iterator<Column> referencedColumnsIterator) {
+	public void addReferencedColumns(List<Column> referencedColumns) {
-		while ( referencedColumnsIterator.hasNext() ) {
+		for (Column referencedColumn : referencedColumns) {
-			Selectable col = referencedColumnsIterator.next();
+//			if ( !referencedColumn.isFormula() ) {
-			if ( !col.isFormula() ) {
+				addReferencedColumn( referencedColumn );
-				addReferencedColumn( (Column) col );
+//			}
-			}
 		}
 	}
 

hibernate-core/src/main/java/org/hibernate/mapping/IndexedCollection.java

@@ -6,7 +6,6 @@
  */
 package org.hibernate.mapping;
 
-import java.util.Iterator;
 import java.util.function.Supplier;
 
 import org.hibernate.MappingException;
@@ -76,7 +75,7 @@ public abstract class IndexedCollection extends Collection {
 			}
 			getCollectionTable().setPrimaryKey(pk);
 		}
-		else {
+//		else {
 			// don't create a unique key, 'cos some
 			// databases don't like a UK on nullable
 			// columns
@@ -84,7 +83,7 @@ public abstract class IndexedCollection extends Collection {
 			list.addAll( getKey().getConstraintColumns() );
 			list.addAll( getIndex().getConstraintColumns() );
 			getCollectionTable().createUniqueKey(list);*/
-		}
+//		}
 	}
 
 	public void validate(Mapping mapping) throws MappingException {

hibernate-core/src/main/java/org/hibernate/mapping/ManyToOne.java

@@ -7,12 +7,10 @@
 package org.hibernate.mapping;
 
 import java.util.ArrayList;
-import java.util.Iterator;
 import java.util.Map;
 
 import org.hibernate.MappingException;
 import org.hibernate.boot.spi.MetadataBuildingContext;
-import org.hibernate.boot.spi.MetadataImplementor;
 import org.hibernate.type.EntityType;
 import org.hibernate.type.Type;
 
@@ -64,11 +62,11 @@ public class ManyToOne extends ToOne {
 		}
 	}
 
-	public void createPropertyRefConstraints(Map persistentClasses) {
+	public void createPropertyRefConstraints(Map<String, PersistentClass> persistentClasses) {
 		if (referencedPropertyName!=null) {
 			// Ensure properties are sorted before we create a foreign key
 			sortProperties();
-			PersistentClass pc = (PersistentClass) persistentClasses.get(getReferencedEntityName() );
+			PersistentClass pc = persistentClasses.get(getReferencedEntityName() );
 			
 			Property property = pc.getReferencedProperty( getReferencedPropertyName() );
 			

hibernate-core/src/main/java/org/hibernate/mapping/MappedSuperclass.java

@@ -30,8 +30,8 @@ import java.util.List;
 public class MappedSuperclass {
 	private final MappedSuperclass superMappedSuperclass;
 	private final PersistentClass superPersistentClass;
-	private final List declaredProperties;
+	private final List<Property> declaredProperties;
-	private Class mappedClass;
+	private Class<?> mappedClass;
 	private Property identifierProperty;
 	private Property version;
 	private Component identifierMapper;
@@ -39,7 +39,7 @@ public class MappedSuperclass {
 	public MappedSuperclass(MappedSuperclass superMappedSuperclass, PersistentClass superPersistentClass) {
 		this.superMappedSuperclass = superMappedSuperclass;
 		this.superPersistentClass = superPersistentClass;
-		this.declaredProperties = new ArrayList();
+		this.declaredProperties = new ArrayList<>();
 	}
 
 	/**
@@ -71,28 +71,32 @@ public class MappedSuperclass {
 		return superPersistentClass;
 	}
 
-	public Iterator getDeclaredPropertyIterator() {
+	@Deprecated(since = "6.0")
+	public Iterator<Property> getDeclaredPropertyIterator() {
 		return declaredProperties.iterator();
 	}
 
+	public List<Property> getDeclaredProperties() {
+		return declaredProperties;
+	}
+
 	public void addDeclaredProperty(Property p) {
 		//Do not add duplicate properties
 		//TODO is it efficient enough?
 		String name = p.getName();
-		Iterator it = declaredProperties.iterator();
+		for (Property declaredProperty : declaredProperties) {
-		while (it.hasNext()) {
+			if ( name.equals( declaredProperty.getName() ) ) {
-			if ( name.equals( ((Property)it.next()).getName() ) ) {
 				return;
 			}
 		}
 		declaredProperties.add(p);
 	}
 
-	public Class getMappedClass() {
+	public Class<?> getMappedClass() {
 		return mappedClass;
 	}
 
-	public void setMappedClass(Class mappedClass) {
+	public void setMappedClass(Class<?> mappedClass) {
 		this.mappedClass = mappedClass;
 	}
 
@@ -173,9 +177,7 @@ public class MappedSuperclass {
 	 * @return {@code true} if a property with that name exists; {@code false} if not
 	 */
 	public boolean hasProperty(String name) {
-		final Iterator itr = getDeclaredPropertyIterator();
+		for ( Property property : getDeclaredProperties() ) {
-		while ( itr.hasNext() ) {
-			final Property property = (Property) itr.next();
 			if ( property.getName().equals( name ) ) {
 				return true;
 			}
@@ -210,8 +212,7 @@ public class MappedSuperclass {
 		return false;
 	}
 
-	@SuppressWarnings( "unchecked" )
 	public void prepareForMappingModel() {
-		( (List<Property>) declaredProperties ).sort( Comparator.comparing( Property::getName ) );
+		declaredProperties.sort( Comparator.comparing( Property::getName ) );
 	}
 }

hibernate-core/src/main/java/org/hibernate/mapping/MappingHelper.java

@@ -67,12 +67,7 @@ public final class MappingHelper {
 
 	public static void injectParameters(Object type, Properties parameters) {
 		if ( type instanceof ParameterizedType ) {
-			if ( parameters == null ) {
+			( (ParameterizedType) type ).setParameterValues( parameters == null ? EMPTY_PROPERTIES : parameters );
-				( (ParameterizedType) type ).setParameterValues( EMPTY_PROPERTIES );
-			}
-			else {
-				( (ParameterizedType) type ).setParameterValues( parameters );
-			}
 		}
 		else if ( parameters != null && !parameters.isEmpty() ) {
 			MappingModelCreationLogger.LOGGER.debugf(

hibernate-core/src/main/java/org/hibernate/mapping/PersistentClass.java

@@ -214,9 +214,25 @@ public abstract class PersistentClass implements AttributeContainer, Serializabl
 	}
 
 	/**
-	 * Iterate over subclasses in a special 'order', most derived subclasses
+	 * Get the subclasses in a special 'order', most derived subclasses first.
-	 * first.
 	 */
+	public List<Subclass> getSubclasses() {
+		@SuppressWarnings("unchecked")
+		List<Subclass>[] iters = new List[subclasses.size() + 1];
+		int i = 0;
+		for ( Subclass subclass : subclasses ) {
+			iters[i++] = subclass.getSubclasses();
+		}
+		iters[i] = subclasses;
+		return new JoinedList<>( iters );
+	}
+
+	/**
+	 * Iterate over subclasses in a special 'order', most derived subclasses first.
+	 *
+	 * @deprecated use {@link #getSubclasses()}
+	 */
+	@Deprecated(since = "6.0")
 	public Iterator<Subclass> getSubclassIterator() {
 		@SuppressWarnings("unchecked")
 		Iterator<Subclass>[] iters = new Iterator[subclasses.size() + 1];
@@ -229,13 +245,21 @@ public abstract class PersistentClass implements AttributeContainer, Serializabl
 		return new JoinedIterator<>( iters );
 	}
 
+	public List<PersistentClass> getSubclassClosure() {
+		ArrayList<List<PersistentClass>> lists = new ArrayList<>();
+		lists.add( List.of( this ) );
+		for ( Subclass subclass : getSubclasses() ) {
+			lists.add( subclass.getSubclassClosure() );
+		}
+		return new JoinedList<>( lists );
+	}
+
+	@Deprecated(since = "6.0")
 	public Iterator<PersistentClass> getSubclassClosureIterator() {
 		ArrayList<Iterator<PersistentClass>> iters = new ArrayList<>();
 		iters.add( new SingletonIterator<>( this ) );
-		Iterator<Subclass> iter = getSubclassIterator();
+		for ( Subclass subclass : getSubclasses() ) {
-		while ( iter.hasNext() ) {
+			iters.add( subclass.getSubclassClosureIterator() );
-			PersistentClass clazz =  iter.next();
-			iters.add( clazz.getSubclassClosureIterator() );
 		}
 		return new JoinedIterator<>( iters );
 	}
@@ -244,8 +268,8 @@ public abstract class PersistentClass implements AttributeContainer, Serializabl
 		return getRootTable();
 	}
 
-	public Iterator<Subclass> getDirectSubclasses() {
+	public List<Subclass> getDirectSubclasses() {
-		return subclasses.iterator();
+		return subclasses;
 	}
 
 	@Override
@@ -328,6 +352,9 @@ public abstract class PersistentClass implements AttributeContainer, Serializabl
 	@Deprecated(since = "6.0")
 	public abstract Iterator<Table> getTableClosureIterator();
 
+	public abstract List<KeyValue> getKeyClosure();
+
+	@Deprecated(since = "6.0")
 	public abstract Iterator<KeyValue> getKeyClosureIterator();
 
 	protected void addSubclassProperty(Property prop) {
@@ -783,7 +810,10 @@ public abstract class PersistentClass implements AttributeContainer, Serializabl
 	 * defined in superclasses of the mapping inheritance are not included.
 	 *
 	 * @return An iterator over the "normal" properties.
+	 *
+	 * @deprecated use {@link #getProperties()}
 	 */
+	@Deprecated(since = "6.0")
 	public Iterator<Property> getPropertyIterator() {
 		ArrayList<Iterator<Property>> iterators = new ArrayList<>();
 		iterators.add( properties.iterator() );
@@ -1006,6 +1036,7 @@ public abstract class PersistentClass implements AttributeContainer, Serializabl
 		return getUnjoinedProperties();
 	}
 
+	@Deprecated(since = "6.0")
 	protected Iterator<Selectable> getDiscriminatorColumnIterator() {
 		return Collections.emptyIterator();
 	}
@@ -1113,11 +1144,20 @@ public abstract class PersistentClass implements AttributeContainer, Serializabl
 	}
 
 	// The following methods are added to support @MappedSuperclass in the metamodel
+	public List<Property> getDeclaredProperties() {
+		ArrayList<List<Property>> lists = new ArrayList<>();
+		lists.add( declaredProperties );
+		for (Join join : joins) {
+			lists.add( join.getDeclaredProperties() );
+		}
+		return new JoinedList<>( lists );
+	}
+
+	@Deprecated(since = "6.0")
 	public Iterator<Property> getDeclaredPropertyIterator() {
 		ArrayList<Iterator<Property>> iterators = new ArrayList<>();
 		iterators.add( declaredProperties.iterator() );
-		for ( int i = 0; i < joins.size(); i++ ) {
+		for (Join join : joins) {
-			Join join = joins.get( i );
 			iterators.add( join.getDeclaredPropertyIterator() );
 		}
 		return new JoinedIterator<>( iterators );

hibernate-core/src/main/java/org/hibernate/mapping/PrimaryKey.java

@@ -28,9 +28,7 @@ public class PrimaryKey extends Constraint {
 
 	@Override
 	public void addColumn(Column column) {
-		final Iterator<Column> columnIterator = getTable().getColumnIterator();
+		for ( Column next : getTable().getColumns() ) {
-		while ( columnIterator.hasNext() ) {
-			final Column next = columnIterator.next();
 			if ( next.getCanonicalName().equals( column.getCanonicalName() ) ) {
 				next.setNullable( false );
 				if ( log.isDebugEnabled() ) {
@@ -62,9 +60,9 @@ public class PrimaryKey extends Constraint {
 
 	public String sqlConstraintString(Dialect dialect) {
 		StringBuilder buf = new StringBuilder("primary key (");
-		Iterator iter = getColumnIterator();
+		Iterator<Column> iter = getColumnIterator();
 		while ( iter.hasNext() ) {
-			buf.append( ( (Column) iter.next() ).getQuotedName(dialect) );
+			buf.append( iter.next().getQuotedName(dialect) );
 			if ( iter.hasNext() ) {
 				buf.append(", ");
 			}

hibernate-core/src/main/java/org/hibernate/mapping/RootClass.java

@@ -146,11 +146,16 @@ public class RootClass extends PersistentClass implements TableOwner {
 		return List.of( getTable() );
 	}
 
-	@Override
+	@Override @Deprecated
 	public Iterator<KeyValue> getKeyClosureIterator() {
 		return new SingletonIterator<>( getKey() );
 	}
 
+	@Override
+	public List<KeyValue> getKeyClosure() {
+		return List.of( getKey() );
+	}
+
 	@Override
 	public void addSubclass(Subclass subclass) throws MappingException {
 		super.addSubclass( subclass );
@@ -351,9 +356,7 @@ public class RootClass extends PersistentClass implements TableOwner {
 
 	public Set<Table> getIdentityTables() {
 		Set<Table> tables = new HashSet<>();
-		Iterator<PersistentClass> iter = getSubclassClosureIterator();
+		for ( PersistentClass clazz : getSubclassClosure() ) {
-		while ( iter.hasNext() ) {
-			PersistentClass clazz = iter.next();
 			if ( clazz.isAbstract() == null || !clazz.isAbstract() ) {
 				tables.add( clazz.getIdentityTable() );
 			}

hibernate-core/src/main/java/org/hibernate/mapping/SingleTableSubclass.java

@@ -36,6 +36,7 @@ public class SingleTableSubclass extends Subclass {
 		return new JoinedList<>( getSuperclass().getUnjoinedProperties(), getUnjoinedProperties() );
 	}
 
+	@Deprecated
 	protected Iterator<Selectable> getDiscriminatorColumnIterator() {
 		return isDiscriminatorInsertable() && !getDiscriminator().hasFormula()
 				? getDiscriminator().getColumnIterator()

hibernate-core/src/main/java/org/hibernate/mapping/Subclass.java

@@ -155,7 +155,7 @@ public class Subclass extends PersistentClass {
 		);
 	}
 
-	@Override
+	@Override @Deprecated
 	public Iterator<KeyValue> getKeyClosureIterator() {
 		return new JoinedIterator<>(
 				getSuperclass().getKeyClosureIterator(),
@@ -163,6 +163,14 @@ public class Subclass extends PersistentClass {
 			);
 	}
 
+	@Override
+	public List<KeyValue> getKeyClosure() {
+		return new JoinedList<>(
+				getSuperclass().getKeyClosure(),
+				List.of( getKey() )
+		);
+	}
+
 	@Override
 	protected void addSubclassProperty(Property p) {
 		super.addSubclassProperty(p);

hibernate-core/src/main/java/org/hibernate/mapping/Table.java

@@ -281,6 +281,7 @@ public class Table implements RelationalModel, Serializable, ContributableDataba
 		return columns.size();
 	}
 
+	@Deprecated(since = "6.0")
 	public Iterator<Column> getColumnIterator() {
 		return columns.values().iterator();
 	}
@@ -293,6 +294,7 @@ public class Table implements RelationalModel, Serializable, ContributableDataba
 		return indexes.values().iterator();
 	}
 
+	@Deprecated(since = "6.0")
 	public Iterator<ForeignKey> getForeignKeyIterator() {
 		return foreignKeys.values().iterator();
 	}
@@ -301,11 +303,12 @@ public class Table implements RelationalModel, Serializable, ContributableDataba
 		return Collections.unmodifiableMap( foreignKeys );
 	}
 
+	@Deprecated(since = "6.0")
 	public Iterator<UniqueKey> getUniqueKeyIterator() {
 		return getUniqueKeys().values().iterator();
 	}
 
-	Map<String, UniqueKey> getUniqueKeys() {
+	public Map<String, UniqueKey> getUniqueKeys() {
 		cleanseUniqueKeyMapIfNeeded();
 		return uniqueKeys;
 	}
@@ -425,12 +428,12 @@ public class Table implements RelationalModel, Serializable, ContributableDataba
 				.append( ' ' )
 				.append( dialect.getAddColumnString() );
 
-		Iterator<Column> iter = getColumnIterator();
 		List<String> results = new ArrayList<>();
 
-		while ( iter.hasNext() ) {
+		for ( Column column : getColumns() ) {
-			final Column column = iter.next();
+			final ColumnInformation columnInfo = tableInfo.getColumn(
-			final ColumnInformation columnInfo = tableInfo.getColumn( Identifier.toIdentifier( column.getName(), column.isQuoted() ) );
+					Identifier.toIdentifier( column.getName(), column.isQuoted() )
+			);
 
 			if ( columnInfo == null ) {
 				// the column doesnt exist at all.
@@ -702,7 +705,7 @@ public class Table implements RelationalModel, Serializable, ContributableDataba
 				fk.addColumn( keyColumn );
 			}
 			if ( referencedColumns != null ) {
-				fk.addReferencedColumns( referencedColumns.iterator() );
+				fk.addReferencedColumns( referencedColumns );
 			}
 
 			// NOTE : if the name is null, we will generate an implicit name during second pass processing
@@ -811,10 +814,15 @@ public class Table implements RelationalModel, Serializable, ContributableDataba
 		this.comment = comment;
 	}
 
+	@Deprecated(since = "6.0")
 	public Iterator<String> getCheckConstraintsIterator() {
 		return checkConstraints.iterator();
 	}
 
+	public List<String> getCheckConstraints() {
+		return checkConstraints;
+	}
+
 	@Override
 	public String getExportIdentifier() {
 		return Table.qualify(

hibernate-core/src/main/java/org/hibernate/metamodel/internal/EntityInstantiatorDynamicMap.java

@@ -32,9 +32,7 @@ public class EntityInstantiatorDynamicMap
 
 		entityRoleNames.add( getRoleName() );
 		if ( bootDescriptor.hasSubclasses() ) {
-			final Iterator<PersistentClass> itr = bootDescriptor.getSubclassClosureIterator();
+			for ( PersistentClass subclassInfo : bootDescriptor.getSubclassClosure() ) {
-			while ( itr.hasNext() ) {
-				final PersistentClass subclassInfo = itr.next();
 				entityRoleNames.add( subclassInfo.getEntityName() );
 			}
 		}

hibernate-core/src/main/java/org/hibernate/metamodel/internal/EntityRepresentationStrategyPojoStandard.java

@@ -208,9 +208,7 @@ public class EntityRepresentationStrategyPojoStandard implements EntityRepresent
 			proxyInterfaces.add( mappedClass );
 		}
 
-		final Iterator<Subclass> subclasses = bootDescriptor.getSubclassIterator();
+		for ( Subclass subclass : bootDescriptor.getSubclasses() ) {
-		while ( subclasses.hasNext() ) {
-			final Subclass subclass = subclasses.next();
 			final Class<?> subclassProxy = subclass.getProxyInterface();
 			final Class<?> subclassClass = subclass.getMappedClass();
 			if ( subclassProxy != null && !subclassClass.equals( subclassProxy ) ) {

hibernate-core/src/main/java/org/hibernate/metamodel/internal/MetadataContext.java

@@ -11,7 +11,6 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -273,9 +272,7 @@ public class MetadataContext {
 					applyIdMetadata( safeMapping, jpaMapping );
 					applyVersionAttribute( safeMapping, jpaMapping );
 
-					Iterator<Property> properties = safeMapping.getDeclaredPropertyIterator();
+					for ( Property property : safeMapping.getDeclaredProperties() ) {
-					while ( properties.hasNext() ) {
-						final Property property = properties.next();
 						if ( property.getValue() == safeMapping.getIdentifierMapper() ) {
 							// property represents special handling for id-class mappings but we have already
 							// accounted for the embedded property mappings in #applyIdMetadata &&
@@ -324,9 +321,7 @@ public class MetadataContext {
 					applyVersionAttribute( safeMapping, jpaType );
 //					applyNaturalIdAttribute( safeMapping, jpaType );
 
-					Iterator<Property> properties = safeMapping.getDeclaredPropertyIterator();
+					for ( Property property : safeMapping.getDeclaredProperties() ) {
-					while ( properties.hasNext() ) {
-						final Property property = properties.next();
 						if ( safeMapping.isVersioned() && property == safeMapping.getVersion() ) {
 							// skip the version property, it was already handled previously.
 							continue;

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -1155,9 +1155,7 @@ public abstract class AbstractEntityPersister
 			return true;
 		}
 
-		final Iterator<Subclass> subclassIterator = persistentClass.getSubclassIterator();
+		for ( Subclass subclass : persistentClass.getSubclasses() ) {
-		while ( subclassIterator.hasNext() ) {
-			final Subclass subclass = subclassIterator.next();
 			if ( subclass.isCached() ) {
 				return true;
 			}

hibernate-core/src/main/java/org/hibernate/persister/entity/JoinedSubclassEntityPersister.java

@@ -249,11 +249,11 @@ public class JoinedSubclassEntityPersister extends AbstractEntityPersister {
 		ArrayList<String[]> keyColumnReaders = new ArrayList<>();
 		ArrayList<String[]> keyColumnReaderTemplates = new ArrayList<>();
 		ArrayList<Boolean> cascadeDeletes = new ArrayList<>();
-		Iterator<Table> tItr = persistentClass.getTableClosureIterator();
+		List<Table> tItr = persistentClass.getTableClosure();
-		Iterator<KeyValue> kItr = persistentClass.getKeyClosureIterator();
+		List<KeyValue> kItr = persistentClass.getKeyClosure();
-		while ( tItr.hasNext() ) {
+		for ( int i = 0; i < tItr.size() && i < kItr.size(); i++ ) {
-			final Table table = tItr.next();
+			final Table table = tItr.get(i);
-			final KeyValue key = kItr.next();
+			final KeyValue key = kItr.get(i);
 			final String tableName = determineTableName( table );
 			tableNames.add( tableName );
 			String[] keyCols = new String[idColumnSpan];
@@ -562,26 +562,25 @@ public class JoinedSubclassEntityPersister extends AbstractEntityPersister {
 			notNullColumnNames = null;
 		}
 
-		Iterator<Subclass> siter = persistentClass.getSubclassIterator();
 		int k = 0;
-		while ( siter.hasNext() ) {
+		for ( Subclass subclass : persistentClass.getSubclasses() ) {
-			Subclass sc = siter.next();
+			subclassClosure[k] = subclass.getEntityName();
-			subclassClosure[k] = sc.getEntityName();
+			final Table table = subclass.getTable();
-			final Table table = sc.getTable();
+			subclassNameByTableName.put( table.getName(), subclass.getEntityName() );
-			subclassNameByTableName.put( table.getName(), sc.getEntityName() );
 			try {
 				if ( persistentClass.isPolymorphic() ) {
 					final Object discriminatorValue;
 					if ( explicitDiscriminatorColumnName != null ) {
-						if ( sc.isDiscriminatorValueNull() ) {
+						if ( subclass.isDiscriminatorValueNull() ) {
 							discriminatorValue = NULL_DISCRIMINATOR;
 						}
-						else if ( sc.isDiscriminatorValueNotNull() ) {
+						else if ( subclass.isDiscriminatorValueNotNull() ) {
 							discriminatorValue = NOT_NULL_DISCRIMINATOR;
 						}
 						else {
 							try {
-								discriminatorValue = discriminatorType.getJavaTypeDescriptor().fromString( sc.getDiscriminatorValue() );
+								discriminatorValue = discriminatorType.getJavaTypeDescriptor()
+										.fromString( subclass.getDiscriminatorValue() );
 							}
 							catch (ClassCastException cce) {
 								throw new MappingException( "Illegal discriminator type: " + discriminatorType.getName() );
@@ -595,10 +594,10 @@ public class JoinedSubclassEntityPersister extends AbstractEntityPersister {
 						// we now use subclass ids that are consistent across all
 						// persisters for a class hierarchy, so that the use of
 						// "foo.class = Bar" works in HQL
-						discriminatorValue = sc.getSubclassId();
+						discriminatorValue = subclass.getSubclassId();
 					}
 					initDiscriminatorProperties( factory, k, table, discriminatorValue );
-					subclassesByDiscriminatorValue.put( discriminatorValue, sc.getEntityName() );
+					subclassesByDiscriminatorValue.put( discriminatorValue, subclass.getEntityName() );
 					int id = getTableId(
 							table.getQualifiedName(
 									factory.getSqlStringGenerationContext()
@@ -700,9 +699,7 @@ public class JoinedSubclassEntityPersister extends AbstractEntityPersister {
 		// included when one of the collected class names is used in TREAT
 		final Set<String> classNames = new HashSet<>();
 
-		final Iterator<Subclass> itr = persistentClass.getDirectSubclasses();
+		for ( Subclass subclass : persistentClass.getDirectSubclasses() ) {
-		while ( itr.hasNext() ) {
-			final Subclass subclass = itr.next();
 			final Set<String> subclassSubclassNames = processPersistentClassHierarchy(
 					subclass,
 					false,

hibernate-core/src/main/java/org/hibernate/persister/entity/SingleTableEntityPersister.java

@@ -9,7 +9,6 @@ package org.hibernate.persister.entity;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -412,23 +411,21 @@ public class SingleTableEntityPersister extends AbstractEntityPersister {
 
 		// SUBCLASSES
 		if ( persistentClass.isPolymorphic() ) {
-			Iterator<Subclass> subclasses = persistentClass.getSubclassIterator();
 			int k = 1;
-			while ( subclasses.hasNext() ) {
+			for ( Subclass subclass : persistentClass.getSubclasses() ) {
-				Subclass sc = subclasses.next();
+				subclassClosure[k++] = subclass.getEntityName();
-				subclassClosure[k++] = sc.getEntityName();
+				if ( subclass.isDiscriminatorValueNull() ) {
-				if ( sc.isDiscriminatorValueNull() ) {
+					addSubclassByDiscriminatorValue( subclassesByDiscriminatorValueLocal, NULL_DISCRIMINATOR, subclass.getEntityName() );
-					addSubclassByDiscriminatorValue( subclassesByDiscriminatorValueLocal, NULL_DISCRIMINATOR, sc.getEntityName() );
 				}
-				else if ( sc.isDiscriminatorValueNotNull() ) {
+				else if ( subclass.isDiscriminatorValueNotNull() ) {
-					addSubclassByDiscriminatorValue( subclassesByDiscriminatorValueLocal, NOT_NULL_DISCRIMINATOR, sc.getEntityName() );
+					addSubclassByDiscriminatorValue( subclassesByDiscriminatorValueLocal, NOT_NULL_DISCRIMINATOR, subclass.getEntityName() );
 				}
 				else {
 					try {
 						addSubclassByDiscriminatorValue(
 								subclassesByDiscriminatorValueLocal,
-								discriminatorType.getJavaTypeDescriptor().fromString( sc.getDiscriminatorValue() ),
+								discriminatorType.getJavaTypeDescriptor().fromString( subclass.getDiscriminatorValue() ),
-								sc.getEntityName()
+								subclass.getEntityName()
 						);
 					}
 					catch (ClassCastException cce) {

hibernate-core/src/main/java/org/hibernate/persister/entity/UnionSubclassEntityPersister.java

@@ -34,8 +34,7 @@ import org.hibernate.id.IdentityGenerator;
 import org.hibernate.internal.FilterAliasGenerator;
 import org.hibernate.internal.StaticFilterAliasGenerator;
 import org.hibernate.internal.util.collections.ArrayHelper;
-import org.hibernate.internal.util.collections.JoinedIterator;
+import org.hibernate.internal.util.collections.JoinedList;
-import org.hibernate.internal.util.collections.SingletonIterator;
 import org.hibernate.mapping.Column;
 import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.Subclass;
@@ -162,9 +161,7 @@ public class UnionSubclassEntityPersister extends AbstractEntityPersister {
 				persistentClass.getEntityName()
 		);
 		if ( persistentClass.isPolymorphic() ) {
-			Iterator<Subclass> subclassIter = persistentClass.getSubclassIterator();
+			for ( Subclass subclass : persistentClass.getSubclasses() ) {
-			while ( subclassIter.hasNext() ) {
-				Subclass subclass = subclassIter.next();
 				subclassByDiscriminatorValue.put( subclass.getSubclassId(), subclass.getEntityName() );
 			}
 		}
@@ -196,9 +193,7 @@ public class UnionSubclassEntityPersister extends AbstractEntityPersister {
 			tableExpressions.add( generateSubquery( parentPersistentClass, creationContext.getMetadata() ) );
 			parentPersistentClass = parentPersistentClass.getSuperclass();
 		}
-		final Iterator<PersistentClass> subclassClosureIterator = persistentClass.getSubclassClosureIterator();
+		for ( PersistentClass subPersistentClass : persistentClass.getSubclassClosure() ) {
-		while ( subclassClosureIterator.hasNext() ) {
-			final PersistentClass subPersistentClass = subclassClosureIterator.next();
 			if ( subPersistentClass.hasSubclasses() ) {
 				tableExpressions.add( generateSubquery( subPersistentClass, creationContext.getMetadata() ) );
 			}
@@ -475,13 +470,12 @@ public class UnionSubclassEntityPersister extends AbstractEntityPersister {
 		StringBuilder buf = new StringBuilder()
 				.append( "( " );
 
-		Iterator<PersistentClass> siter = new JoinedIterator<>(
+		List<PersistentClass> classes = new JoinedList<>(
-				new SingletonIterator<>( model ),
+				List.of( model ),
-				model.getSubclassIterator()
+				Collections.unmodifiableList( model.getSubclasses() )
 		);
 
-		while ( siter.hasNext() ) {
+		for ( PersistentClass clazz : classes ) {
-			PersistentClass clazz = siter.next();
 			Table table = clazz.getTable();
 			if ( !table.isAbstractUnionTable() ) {
 				//TODO: move to .sql package!!

hibernate-core/src/main/java/org/hibernate/persister/internal/StandardPersisterClassResolver.java

@@ -28,29 +28,30 @@ import org.hibernate.persister.spi.UnknownPersisterException;
 public class StandardPersisterClassResolver implements PersisterClassResolver {
 
 	@Override
-	public Class<? extends EntityPersister> getEntityPersisterClass(PersistentClass metadata) {
+	public Class<? extends EntityPersister> getEntityPersisterClass(PersistentClass model) {
-		// todo : make sure this is based on an attribute kept on the metamodel in the new code, not the concrete PersistentClass impl found!
+		// todo : make sure this is based on an attribute kept on the metamodel in the new code,
-		if ( RootClass.class.isInstance( metadata ) ) {
+		//        not the concrete PersistentClass impl found!
-			if ( metadata.hasSubclasses() ) {
+		if ( model instanceof RootClass ) {
+			if ( model.hasSubclasses() ) {
 				//If the class has children, we need to find of which kind
-				metadata = (PersistentClass) metadata.getDirectSubclasses().next();
+				model = model.getDirectSubclasses().get(0);
 			}
 			else {
 				return singleTableEntityPersister();
 			}
 		}
-		if ( JoinedSubclass.class.isInstance( metadata ) ) {
+		if ( model instanceof JoinedSubclass ) {
 			return joinedSubclassEntityPersister();
 		}
-		else if ( UnionSubclass.class.isInstance( metadata ) ) {
+		else if ( model instanceof UnionSubclass ) {
 			return unionSubclassEntityPersister();
 		}
-		else if ( SingleTableSubclass.class.isInstance( metadata ) ) {
+		else if ( model instanceof SingleTableSubclass ) {
 			return singleTableEntityPersister();
 		}
 		else {
 			throw new UnknownPersisterException(
-					"Could not determine persister implementation for entity [" + metadata.getEntityName() + "]"
+					"Could not determine persister implementation for entity [" + model.getEntityName() + "]"
 			);
 		}
 	}

hibernate-core/src/main/java/org/hibernate/proxy/pojo/ProxyFactoryHelper.java

@@ -8,7 +8,6 @@ package org.hibernate.proxy.pojo;
 
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.util.Iterator;
 import java.util.Set;
 
 import org.hibernate.HibernateException;
@@ -50,9 +49,7 @@ public final class ProxyFactoryHelper {
 			proxyInterfaces.add( mappedClass );
 		}
 
-		Iterator<Subclass> subclasses = persistentClass.getSubclassIterator();
+		for ( Subclass subclass : persistentClass.getSubclasses() ) {
-		while ( subclasses.hasNext() ) {
-			final Subclass subclass = subclasses.next();
 			final Class<?> subclassProxy = subclass.getProxyInterface();
 			final Class<?> subclassClass = subclass.getMappedClass();
 			if ( subclassProxy != null && !subclassClass.equals( subclassProxy ) ) {

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/AbstractSchemaMigrator.java

@@ -75,12 +75,9 @@ public abstract class AbstractSchemaMigrator implements SchemaMigrator {
 			HibernateSchemaManagementTool tool,
 			SchemaFilter schemaFilter) {
 		this.tool = tool;
-		if ( schemaFilter == null ) {
+		this.schemaFilter = schemaFilter == null
-			this.schemaFilter = DefaultSchemaFilter.INSTANCE;
+				? DefaultSchemaFilter.INSTANCE
-		}
+				: schemaFilter;
-		else {
-			this.schemaFilter = schemaFilter;
-		}
 	}
 
 	private UniqueConstraintSchemaUpdateStrategy uniqueConstraintStrategy;
@@ -325,9 +322,6 @@ public abstract class AbstractSchemaMigrator implements SchemaMigrator {
 			ExecutionOptions options,
 			SqlStringGenerationContext sqlStringGenerationContext,
 			GenerationTarget... targets) {
-		final Database database = metadata.getDatabase();
-
-		//noinspection unchecked
 		applySqlStrings(
 				false,
 				table.sqlAlterStrings(
@@ -394,9 +388,7 @@ public abstract class AbstractSchemaMigrator implements SchemaMigrator {
 		if ( uniqueConstraintStrategy != UniqueConstraintSchemaUpdateStrategy.SKIP ) {
 			final Exporter<Constraint> exporter = dialect.getUniqueKeyExporter();
 
-			final Iterator ukItr = table.getUniqueKeyIterator();
+			for ( UniqueKey uniqueKey : table.getUniqueKeys().values() ) {
-			while ( ukItr.hasNext() ) {
-				final UniqueKey uniqueKey = (UniqueKey) ukItr.next();
 				// Skip if index already exists. Most of the time, this
 				// won't work since most Dialects use Constraints. However,
 				// keep it for the few that do use Indexes.
@@ -449,10 +441,7 @@ public abstract class AbstractSchemaMigrator implements SchemaMigrator {
 		if ( dialect.hasAlterTable() ) {
 			final Exporter<ForeignKey> exporter = dialect.getForeignKeyExporter();
 
-			@SuppressWarnings("unchecked")
+			for ( ForeignKey foreignKey : table.getForeignKeys().values() ) {
-			final Iterator<ForeignKey> fkItr = table.getForeignKeyIterator();
-			while ( fkItr.hasNext() ) {
-				final ForeignKey foreignKey = fkItr.next();
 				if ( foreignKey.isPhysicalConstraint() && foreignKey.isCreationEnabled() ) {
 					boolean existingForeignKeyFound = false;
 					if ( tableInformation != null ) {

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/AbstractSchemaValidator.java

@@ -6,7 +6,6 @@
  */
 package org.hibernate.tool.schema.internal;
 
-import java.util.Iterator;
 import java.util.Locale;
 
 import org.hibernate.boot.Metadata;
@@ -137,9 +136,7 @@ public abstract class AbstractSchemaValidator implements SchemaValidator {
 			);
 		}
 
-		final Iterator<Column> columnIter = table.getColumnIterator();
+		for ( Column column : table.getColumns() ) {
-		while ( columnIter.hasNext() ) {
-			final Column column = columnIter.next();
 			final ColumnInformation existingColumn = tableInformation.getColumn( Identifier.toIdentifier( column.getQuotedName() ) );
 			if ( existingColumn == null ) {
 				throw new SchemaManagementException(

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/SchemaCreatorImpl.java

@@ -397,9 +397,7 @@ public class SchemaCreatorImpl implements SchemaCreator {
 				}
 
 				// unique keys
-				final Iterator<UniqueKey> ukItr = table.getUniqueKeyIterator();
+				for ( UniqueKey uniqueKey : table.getUniqueKeys().values() ) {
-				while ( ukItr.hasNext() ) {
-					final UniqueKey uniqueKey = ukItr.next();
 					checkExportIdentifier( uniqueKey, exportIdentifiers );
 					applySqlStrings(
 							dialect.getUniqueKeyExporter().getSqlCreateStrings( uniqueKey, metadata,
@@ -431,9 +429,7 @@ public class SchemaCreatorImpl implements SchemaCreator {
 				}
 
 				// foreign keys
-				final Iterator<ForeignKey> fkItr = table.getForeignKeyIterator();
+				for ( ForeignKey foreignKey : table.getForeignKeys().values() ) {
-				while ( fkItr.hasNext() ) {
-					final ForeignKey foreignKey = fkItr.next();
 					applySqlStrings(
 							dialect.getForeignKeyExporter().getSqlCreateStrings( foreignKey, metadata,
 									sqlStringGenerationContext

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/SchemaDropperImpl.java

@@ -10,7 +10,6 @@ import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -370,9 +369,7 @@ public class SchemaDropperImpl implements SchemaDropper {
 				continue;
 			}
 
-			final Iterator<ForeignKey> fks = table.getForeignKeyIterator();
+			for ( ForeignKey foreignKey : table.getForeignKeys().values() ) {
-			while ( fks.hasNext() ) {
-				final ForeignKey foreignKey = fks.next();
 				applySqlStrings(
 						dialect.getForeignKeyExporter().getSqlDropStrings( foreignKey, metadata,
 								sqlStringGenerationContext

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/StandardTableExporter.java

@@ -20,6 +20,7 @@ import org.hibernate.boot.model.relational.QualifiedNameParser;
 import org.hibernate.boot.model.relational.SqlStringGenerationContext;
 import org.hibernate.boot.spi.MetadataImplementor;
 import org.hibernate.dialect.Dialect;
+import org.hibernate.internal.util.StringHelper;
 import org.hibernate.mapping.Column;
 import org.hibernate.mapping.Constraint;
 import org.hibernate.mapping.Table;
@@ -70,10 +71,8 @@ public class StandardTableExporter implements Exporter<Table> {
 				pkColName = pkColumn.getQuotedName( dialect );
 			}
 
-			final Iterator columnItr = table.getColumnIterator();
 			boolean isFirst = true;
-			while ( columnItr.hasNext() ) {
+			for ( Column col : table.getColumns() ) {
-				final Column col = (Column) columnItr.next();
 				if ( isFirst ) {
 					isFirst = false;
 				}
@@ -162,7 +161,7 @@ public class StandardTableExporter implements Exporter<Table> {
 
 		applyInitCommands( table, sqlStrings, context );
 
-			return sqlStrings.toArray( new String[ sqlStrings.size() ] );
+			return sqlStrings.toArray(StringHelper.EMPTY_STRINGS);
 		}
 		catch (Exception e) {
 			throw new MappingException( "Error creating SQL create commands for table : " + tableName, e );
@@ -174,9 +173,7 @@ public class StandardTableExporter implements Exporter<Table> {
 			if ( table.getComment() != null ) {
 				sqlStrings.add( "comment on table " + tableName + " is '" + table.getComment() + "'" );
 			}
-			final Iterator iter = table.getColumnIterator();
+			for ( Column column : table.getColumns() ) {
-			while ( iter.hasNext() ) {
-				Column column = (Column) iter.next();
 				String columnComment = column.getComment();
 				if ( columnComment != null ) {
 					sqlStrings.add( "comment on column " + tableName + '.' + column.getQuotedName( dialect ) + " is '" + columnComment + "'" );
@@ -197,10 +194,9 @@ public class StandardTableExporter implements Exporter<Table> {
 
 	protected void applyTableCheck(Table table, StringBuilder buf) {
 		if ( dialect.supportsTableCheck() ) {
-			final Iterator<String> checkConstraints = table.getCheckConstraintsIterator();
+			for (String constraint : table.getCheckConstraints() ) {
-			while ( checkConstraints.hasNext() ) {
 				buf.append( ", check (" )
-						.append( checkConstraints.next() )
+						.append( constraint )
 						.append( ')' );
 			}
 		}

hibernate-core/src/main/java/org/hibernate/tuple/DynamicMapInstantiator.java

@@ -8,7 +8,6 @@ package org.hibernate.tuple;
 
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 
@@ -28,9 +27,7 @@ public class DynamicMapInstantiator implements Instantiator {
 		this.roleName = mappingInfo.getEntityName();
 		isInstanceEntityNames.add( roleName );
 		if ( mappingInfo.hasSubclasses() ) {
-			Iterator<PersistentClass> itr = mappingInfo.getSubclassClosureIterator();
+			for ( PersistentClass subclassInfo : mappingInfo.getSubclassClosure() ) {
-			while ( itr.hasNext() ) {
-				final PersistentClass subclassInfo = itr.next();
 				isInstanceEntityNames.add( subclassInfo.getEntityName() );
 			}
 		}

hibernate-core/src/main/java/org/hibernate/tuple/entity/EntityMetamodel.java

@@ -35,6 +35,7 @@ import org.hibernate.internal.util.collections.CollectionHelper;
 import org.hibernate.mapping.Component;
 import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.Property;
+import org.hibernate.mapping.Subclass;
 import org.hibernate.persister.entity.EntityPersister;
 import org.hibernate.persister.spi.PersisterCreationContext;
 import org.hibernate.tuple.GenerationTiming;
@@ -404,10 +405,9 @@ public class EntityMetamodel implements Serializable {
 		hasCollections = foundCollection;
 		mutablePropertiesIndexes = mutableIndexes;
 
-		Iterator<?> iter = persistentClass.getSubclassIterator();
 		final Set<String> subclassEntityNamesLocal = new HashSet<>();
-		while ( iter.hasNext() ) {
+		for ( Subclass subclass : persistentClass.getSubclasses() ) {
-			subclassEntityNamesLocal.add( ( (PersistentClass) iter.next() ).getEntityName() );
+			subclassEntityNamesLocal.add( subclass.getEntityName() );
 		}
 		subclassEntityNamesLocal.add( name );
 		subclassEntityNames = CollectionHelper.toSmallSet( subclassEntityNamesLocal );
@@ -415,10 +415,8 @@ public class EntityMetamodel implements Serializable {
 		HashMap<Class<?>, String> entityNameByInheritanceClassMapLocal = new HashMap<>();
 		if ( persistentClass.hasPojoRepresentation() ) {
 			entityNameByInheritanceClassMapLocal.put( persistentClass.getMappedClass(), persistentClass.getEntityName() );
-			iter = persistentClass.getSubclassIterator();
+			for ( Subclass subclass : persistentClass.getSubclasses() ) {
-			while ( iter.hasNext() ) {
+				entityNameByInheritanceClassMapLocal.put( subclass.getMappedClass(), subclass.getEntityName() );
-				final PersistentClass pc = ( PersistentClass ) iter.next();
-				entityNameByInheritanceClassMapLocal.put( pc.getMappedClass(), pc.getEntityName() );
 			}
 		}
 		entityNameByInheritenceClassMap = CollectionHelper.toSmallMap( entityNameByInheritanceClassMapLocal );

hibernate-envers/src/main/java/org/hibernate/envers/configuration/internal/metadata/CollectionMappedByResolver.java

@@ -22,7 +22,6 @@ import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.Property;
 import org.hibernate.mapping.Selectable;
 import org.hibernate.mapping.Table;
-import org.hibernate.mapping.Value;
 
 import org.jboss.logging.Logger;
 
@@ -149,12 +148,10 @@ public class CollectionMappedByResolver {
 	}
 
 	private static String searchMappedByKey(PersistentClass referencedClass, Collection collectionValue) {
-		final Iterator<KeyValue> assocIdClassProps = referencedClass.getKeyClosureIterator();
+		for ( KeyValue keyValue : referencedClass.getKeyClosure() ) {
-		while ( assocIdClassProps.hasNext() ) {
-			final Value value = assocIdClassProps.next();
 			// make sure it's a 'Component' because IdClass is registered as this type.
-			if ( value instanceof Component ) {
+			if ( keyValue instanceof Component ) {
-				final Component component = (Component) value;
+				final Component component = (Component) keyValue;
 				final Iterator<Property> componentPropertyIterator = component.getPropertyIterator();
 				while ( componentPropertyIterator.hasNext() ) {
 					final Property property = componentPropertyIterator.next();