From c5c3bb8ac8ae3ec657126d0ac01b55f416a8ff99 Mon Sep 17 00:00:00 2001
From: Jan Schatteman <jschatte@redhat.com>
Date: Fri, 9 Jun 2023 21:57:34 +0200
Subject: [PATCH] HHH-16515 - Add o.h.exception to nullness checking

HHH-16515 - Add o.h.integrator to nullness checking

HHH-16515 - Add o.h.service to nullness checking

HHH-16515 - Add o.h.engine.jndi to nullness checking

HHH-16515 - Add o.h.engine.config to nullness checking

Signed-off-by: Jan Schatteman <jschatte@redhat.com>
---
 gradle/java-module.gradle                     |  2 +-
 .../boot/internal/MetadataBuilderImpl.java    |  4 --
 .../BootstrapServiceRegistryBuilder.java      |  2 +-
 .../StandardServiceRegistryBuilder.java       |  2 +-
 .../BootstrapServiceRegistryImpl.java         |  8 ++-
 .../internal/StandardServiceRegistryImpl.java | 24 +++++---
 .../cache/spi/access/AccessType.java          |  4 +-
 .../internal/ConfigurationServiceImpl.java    | 14 +++--
 .../config/spi/ConfigurationService.java      | 12 ++--
 .../engine/config/spi/StandardConverters.java | 14 +----
 .../engine/jndi/internal/JndiServiceImpl.java |  3 +-
 .../internal/AbstractJtaPlatform.java         |  3 +-
 .../internal/AtomikosJtaPlatform.java         |  3 +-
 .../internal/BitronixJtaPlatform.java         |  3 +-
 .../internal/JBossStandAloneJtaPlatform.java  |  9 +--
 .../platform/internal/JOTMJtaPlatform.java    |  3 +-
 .../internal/JtaPlatformInitiator.java        |  5 +-
 .../JtaPlatformResolverInitiator.java         |  3 +-
 .../internal/StandardJtaPlatformResolver.java |  3 +-
 .../internal/WebSphereLibertyJtaPlatform.java |  4 +-
 .../WildFlyStandAloneJtaPlatform.java         |  9 +--
 .../ConstraintViolationException.java         | 10 ++--
 .../internal/SQLExceptionTypeDelegate.java    |  4 +-
 .../internal/SQLStateConversionDelegate.java  |  4 +-
 .../StandardSQLExceptionConverter.java        |  4 +-
 .../spi/SQLExceptionConversionDelegate.java   |  4 +-
 ...platedViolatedConstraintNameExtractor.java | 10 +++-
 .../spi/ViolatedConstraintNameExtractor.java  |  4 +-
 .../id/SequenceMismatchStrategy.java          |  4 +-
 .../internal/IntegratorServiceImpl.java       | 20 ++++---
 .../util/config/ConfigurationHelper.java      |  4 --
 .../hibernate/service/ServiceRegistry.java    |  6 +-
 .../internal/AbstractServiceRegistryImpl.java | 53 +++++++++---------
 ...sionFactoryServiceRegistryBuilderImpl.java |  2 +-
 ...sionFactoryServiceRegistryFactoryImpl.java |  3 +-
 .../SessionFactoryServiceRegistryImpl.java    | 28 +++++++---
 .../hibernate/service/spi/ServiceBinding.java |  6 +-
 .../spi/ServiceRegistryImplementor.java       |  6 +-
 .../stat/internal/StatisticsInitiator.java    |  7 ++-
 .../hibernate/type/WrapperArrayHandling.java  |  4 +-
 .../connection/ConnectionCreatorTest.java     | 56 ++++++++++++++-----
 .../hibernate/stat/HibernateQueryMetrics.java |  3 +-
 .../boot/ServiceRegistryTestingImpl.java      | 20 +++++--
 .../validation/MockSessionFactory.java        |  2 +-
 44 files changed, 249 insertions(+), 149 deletions(-)

diff --git a/gradle/java-module.gradle b/gradle/java-module.gradle
index 7932564bf1..376962189c 100644
--- a/gradle/java-module.gradle
+++ b/gradle/java-module.gradle
@@ -544,7 +544,7 @@ checkerFramework {
 	extraJavacArgs = [
             '-AsuppressWarnings=initialization',
             // stubs is passed directly through options.compilerArgumentProviders
-            '-AonlyDefs=^org\\.hibernate\\.(jpamodelgen|spi|pretty|stat|engine\\.(profile|transaction)|(action|context|bytecode)\\.spi)\\.'
+            '-AonlyDefs=^org\\.hibernate\\.(exception|integrator|jpamodelgen|service|spi|pretty|stat|engine\\.(config|jndi|profile|transaction)|(action|context|bytecode)\\.spi)\\.'
 	]
 }
 
diff --git a/hibernate-core/src/main/java/org/hibernate/boot/internal/MetadataBuilderImpl.java b/hibernate-core/src/main/java/org/hibernate/boot/internal/MetadataBuilderImpl.java
index 4bb559fb35..3ccb42386f 100644
--- a/hibernate-core/src/main/java/org/hibernate/boot/internal/MetadataBuilderImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/boot/internal/MetadataBuilderImpl.java
@@ -659,10 +659,6 @@ public class MetadataBuilderImpl implements MetadataBuilderImplementor, TypeCont
 			this.sharedCacheMode = configService.getSetting(
 					AvailableSettings.JAKARTA_SHARED_CACHE_MODE,
 					value -> {
-						if ( value == null ) {
-							return null;
-						}
-
 						if ( value instanceof SharedCacheMode ) {
 							return (SharedCacheMode) value;
 						}
diff --git a/hibernate-core/src/main/java/org/hibernate/boot/registry/BootstrapServiceRegistryBuilder.java b/hibernate-core/src/main/java/org/hibernate/boot/registry/BootstrapServiceRegistryBuilder.java
index 6c298370e1..4740514a0a 100644
--- a/hibernate-core/src/main/java/org/hibernate/boot/registry/BootstrapServiceRegistryBuilder.java
+++ b/hibernate-core/src/main/java/org/hibernate/boot/registry/BootstrapServiceRegistryBuilder.java
@@ -187,7 +187,7 @@ public class BootstrapServiceRegistryBuilder {
 			classLoaderService = providedClassLoaderService;
 		}
 
-		final IntegratorServiceImpl integratorService = new IntegratorServiceImpl(
+		final IntegratorServiceImpl integratorService = IntegratorServiceImpl.create(
 				providedIntegrators,
 				classLoaderService
 		);
diff --git a/hibernate-core/src/main/java/org/hibernate/boot/registry/StandardServiceRegistryBuilder.java b/hibernate-core/src/main/java/org/hibernate/boot/registry/StandardServiceRegistryBuilder.java
index b66523e066..7e772aab14 100644
--- a/hibernate-core/src/main/java/org/hibernate/boot/registry/StandardServiceRegistryBuilder.java
+++ b/hibernate-core/src/main/java/org/hibernate/boot/registry/StandardServiceRegistryBuilder.java
@@ -365,7 +365,7 @@ public class StandardServiceRegistryBuilder {
 		settingsCopy.put( LOADED_CONFIG_KEY, aggregatedCfgXml );
 		ConfigurationHelper.resolvePlaceHolders( settingsCopy );
 
-		return new StandardServiceRegistryImpl(
+		return StandardServiceRegistryImpl.create(
 				autoCloseRegistry,
 				bootstrapServiceRegistry,
 				initiators,
diff --git a/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/BootstrapServiceRegistryImpl.java b/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/BootstrapServiceRegistryImpl.java
index a799553772..9b6de3c3e5 100644
--- a/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/BootstrapServiceRegistryImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/BootstrapServiceRegistryImpl.java
@@ -29,6 +29,8 @@ import org.hibernate.service.spi.ServiceInitiator;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 import org.hibernate.service.spi.Stoppable;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * {@link ServiceRegistry} implementation containing specialized "bootstrap" services, specifically:<ul>
  *     <li>{@link ClassLoaderService}</li>
@@ -117,7 +119,7 @@ public class BootstrapServiceRegistryImpl
 		this.integratorServiceBinding = new ServiceBinding<>(
 				this,
 				IntegratorService.class,
-				new IntegratorServiceImpl( providedIntegrators, classLoaderService )
+				IntegratorServiceImpl.create( providedIntegrators, classLoaderService )
 		);
 	}
 
@@ -185,7 +187,7 @@ public class BootstrapServiceRegistryImpl
 
 
 	@Override
-	public <R extends Service> R getService(Class<R> serviceRole) {
+	public <R extends Service> @Nullable R getService(Class<R> serviceRole) {
 		final ServiceBinding<R> binding = locateServiceBinding( serviceRole );
 		return binding == null ? null : binding.getService();
 	}
@@ -235,7 +237,7 @@ public class BootstrapServiceRegistryImpl
 	}
 
 	@Override
-	public ServiceRegistry getParentServiceRegistry() {
+	public @Nullable ServiceRegistry getParentServiceRegistry() {
 		return null;
 	}
 
diff --git a/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/StandardServiceRegistryImpl.java b/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/StandardServiceRegistryImpl.java
index aa4d2cff43..eae8a15480 100644
--- a/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/StandardServiceRegistryImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/boot/registry/internal/StandardServiceRegistryImpl.java
@@ -30,6 +30,14 @@ public class StandardServiceRegistryImpl extends AbstractServiceRegistryImpl imp
 	//Access to this field requires synchronization on -this-
 	private Map<String,Object> configurationValues;
 
+	protected StandardServiceRegistryImpl(
+			boolean autoCloseRegistry,
+			BootstrapServiceRegistry bootstrapServiceRegistry,
+			Map<String,Object> configurationValues) {
+		super( bootstrapServiceRegistry, autoCloseRegistry );
+		this.configurationValues = configurationValues;
+	}
+
 	/**
 	 * Constructs a StandardServiceRegistryImpl.  Should not be instantiated directly; use
 	 * {@link org.hibernate.boot.registry.StandardServiceRegistryBuilder} instead
@@ -41,12 +49,13 @@ public class StandardServiceRegistryImpl extends AbstractServiceRegistryImpl imp
 	 *
 	 * @see org.hibernate.boot.registry.StandardServiceRegistryBuilder
 	 */
-	public StandardServiceRegistryImpl(
+	public static StandardServiceRegistryImpl create(
 			BootstrapServiceRegistry bootstrapServiceRegistry,
 			List<StandardServiceInitiator<?>> serviceInitiators,
 			List<ProvidedService<?>> providedServices,
 			Map<String,Object> configurationValues) {
-		this( true, bootstrapServiceRegistry, serviceInitiators, providedServices, configurationValues );
+
+		return create( true, bootstrapServiceRegistry, serviceInitiators, providedServices, configurationValues );
 	}
 
 	/**
@@ -62,20 +71,21 @@ public class StandardServiceRegistryImpl extends AbstractServiceRegistryImpl imp
 	 *
 	 * @see org.hibernate.boot.registry.StandardServiceRegistryBuilder
 	 */
-	public StandardServiceRegistryImpl(
+	public static StandardServiceRegistryImpl create(
 			boolean autoCloseRegistry,
 			BootstrapServiceRegistry bootstrapServiceRegistry,
 			List<StandardServiceInitiator<?>> serviceInitiators,
 			List<ProvidedService<?>> providedServices,
 			Map<String,Object> configurationValues) {
-		super( bootstrapServiceRegistry, autoCloseRegistry );
 
-		this.configurationValues = configurationValues;
+		StandardServiceRegistryImpl instance = new StandardServiceRegistryImpl( autoCloseRegistry, bootstrapServiceRegistry, configurationValues );
+		instance.initialize();
+		instance.applyServiceRegistrations( serviceInitiators, providedServices );
 
-		applyServiceRegistrations( serviceInitiators, providedServices );
+		return instance;
 	}
 
-	private void applyServiceRegistrations(List<StandardServiceInitiator<?>> serviceInitiators, List<ProvidedService<?>> providedServices) {
+	protected void applyServiceRegistrations(List<StandardServiceInitiator<?>> serviceInitiators, List<ProvidedService<?>> providedServices) {
 		try {
 			// process initiators
 			for ( ServiceInitiator<?> initiator : serviceInitiators ) {
diff --git a/hibernate-core/src/main/java/org/hibernate/cache/spi/access/AccessType.java b/hibernate-core/src/main/java/org/hibernate/cache/spi/access/AccessType.java
index 8f903f54c7..759079e69e 100644
--- a/hibernate-core/src/main/java/org/hibernate/cache/spi/access/AccessType.java
+++ b/hibernate-core/src/main/java/org/hibernate/cache/spi/access/AccessType.java
@@ -8,6 +8,8 @@ package org.hibernate.cache.spi.access;
 
 import java.util.Locale;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Enumerates the policies for managing concurrent access to the shared
  * second-level cache.
@@ -70,7 +72,7 @@ public enum AccessType {
 	 *
 	 * @see #getExternalName()
 	 */
-	public static AccessType fromExternalName(String externalName) {
+	public static AccessType fromExternalName(@Nullable String externalName) {
 		if ( externalName == null ) {
 			return null;
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/config/internal/ConfigurationServiceImpl.java b/hibernate-core/src/main/java/org/hibernate/engine/config/internal/ConfigurationServiceImpl.java
index cd646ffd2c..a959eead68 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/config/internal/ConfigurationServiceImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/config/internal/ConfigurationServiceImpl.java
@@ -13,11 +13,15 @@ import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.boot.registry.classloading.spi.ClassLoadingException;
 import org.hibernate.engine.config.spi.ConfigurationService;
 import org.hibernate.internal.CoreMessageLogger;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.service.spi.ServiceRegistryAwareService;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 
 import org.jboss.logging.Logger;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.checker.nullness.qual.PolyNull;
+
 /**
  * The standard {@link ConfigurationService} implementation.
  *
@@ -52,12 +56,12 @@ public class ConfigurationServiceImpl implements ConfigurationService, ServiceRe
 	}
 
 	@Override
-	public <T> T getSetting(String name, Converter<T> converter) {
+	public <T> @Nullable T getSetting(String name, Converter<T> converter) {
 		return getSetting( name, converter, null );
 	}
 
 	@Override
-	public <T> T getSetting(String name, Converter<T> converter, T defaultValue) {
+	public <T> @PolyNull T getSetting(String name, Converter<T> converter, @PolyNull T defaultValue) {
 		final Object value = settings.get( name );
 		if ( value == null ) {
 			return defaultValue;
@@ -67,14 +71,14 @@ public class ConfigurationServiceImpl implements ConfigurationService, ServiceRe
 	}
 
 	@Override
-	public <T> T getSetting(String name, Class<T> expected, T defaultValue) {
+	public <T> @PolyNull T getSetting(String name, Class<T> expected, @PolyNull T defaultValue) {
 		final Object value = settings.get( name );
 		final T target = cast( expected, value );
 		return target !=null ? target : defaultValue;
 	}
 
 	@SuppressWarnings("unchecked")
-	public <T> T cast(Class<T> expected, Object candidate){
+	public <T> @Nullable T cast(Class<T> expected, @Nullable Object candidate){
 		if (candidate == null) {
 			return null;
 		}
@@ -89,7 +93,7 @@ public class ConfigurationServiceImpl implements ConfigurationService, ServiceRe
 		}
 		else {
 			try {
-				target = serviceRegistry.getService( ClassLoaderService.class ).classForName( candidate.toString() );
+				target = NullnessUtil.castNonNull( serviceRegistry.getService( ClassLoaderService.class ) ).classForName( candidate.toString() );
 			}
 			catch ( ClassLoadingException e ) {
 				LOG.debugf( "Unable to locate %s implementation class %s", expected.getName(), candidate.toString() );
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/config/spi/ConfigurationService.java b/hibernate-core/src/main/java/org/hibernate/engine/config/spi/ConfigurationService.java
index 63a9a27bb6..6e9ecd5b4b 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/config/spi/ConfigurationService.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/config/spi/ConfigurationService.java
@@ -10,6 +10,10 @@ import java.util.Map;
 
 import org.hibernate.service.Service;
 
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.checker.nullness.qual.PolyNull;
+
 /**
  * Provides access to the initial user-provided configuration values.  Generally speaking
  * these values come from:<ul>
@@ -38,7 +42,7 @@ public interface ConfigurationService extends Service {
 	 *
 	 * @return The converted (typed) setting.  May return {@code null} (see {@link #getSetting(String, Class, Object)})
 	 */
-	<T> T getSetting(String name, Converter<T> converter);
+	<T> @Nullable T getSetting(String name, Converter<T> converter);
 
 	/**
 	 * Get the named setting, using the specified converter and default value.
@@ -50,7 +54,7 @@ public interface ConfigurationService extends Service {
 	 *
 	 * @return The converted (typed) setting.  Will be the defaultValue if no such setting was defined.
 	 */
-	<T> T getSetting(String name, Converter<T> converter, T defaultValue);
+	<T> @PolyNull T getSetting(String name, Converter<T> converter, @PolyNull T defaultValue);
 
 	/**
 	 * Get the named setting.  Differs from the form taking a Converter in that here we expect to have a simple
@@ -63,7 +67,7 @@ public interface ConfigurationService extends Service {
 	 *
 	 * @return The converted (typed) setting.  Will be the defaultValue if no such setting was defined.
 	 */
-	<T> T getSetting(String name, Class<T> expected, T defaultValue);
+	<T> @PolyNull T getSetting(String name, Class<T> expected, @PolyNull T defaultValue);
 
 	/**
 	 * Simple conversion contract for converting an untyped object to a specified type.
@@ -78,6 +82,6 @@ public interface ConfigurationService extends Service {
 		 *
 		 * @return The converted (typed) value.
 		 */
-		T convert(Object value);
+		@NonNull T convert(Object value);
 	}
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/config/spi/StandardConverters.java b/hibernate-core/src/main/java/org/hibernate/engine/config/spi/StandardConverters.java
index 14fa38aef9..b2684fe25d 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/config/spi/StandardConverters.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/config/spi/StandardConverters.java
@@ -7,6 +7,8 @@
 package org.hibernate.engine.config.spi;
 
 
+import org.checkerframework.checker.nullness.qual.PolyNull;
+
 import static org.hibernate.engine.config.spi.ConfigurationService.Converter;
 
 /**
@@ -18,10 +20,6 @@ public class StandardConverters {
 	public static final Converter<Boolean> BOOLEAN = StandardConverters::asBoolean;
 
 	public static Boolean asBoolean(Object value) {
-		if ( value == null ) {
-			throw new IllegalArgumentException( "Null value passed to convert" );
-		}
-
 		return value instanceof Boolean
 				? (Boolean) value
 				: Boolean.parseBoolean( value.toString() );
@@ -30,20 +28,12 @@ public class StandardConverters {
 	public static final Converter<String> STRING = StandardConverters::asString;
 
 	public static String asString(Object value) {
-		if ( value == null ) {
-			throw new IllegalArgumentException( "Null value passed to convert" );
-		}
-
 		return value.toString();
 	}
 
 	public static final Converter<Integer> INTEGER = StandardConverters::asInteger;
 
 	public static Integer asInteger(Object value) {
-		if ( value == null ) {
-			throw new IllegalArgumentException( "Null value passed to convert" );
-		}
-
 		if ( value instanceof Number ) {
 			return ( (Number) value ).intValue();
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/jndi/internal/JndiServiceImpl.java b/hibernate-core/src/main/java/org/hibernate/engine/jndi/internal/JndiServiceImpl.java
index deec7e54c6..95a08643b2 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/jndi/internal/JndiServiceImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/jndi/internal/JndiServiceImpl.java
@@ -24,6 +24,7 @@ import org.hibernate.engine.jndi.JndiException;
 import org.hibernate.engine.jndi.JndiNameException;
 import org.hibernate.engine.jndi.spi.JndiService;
 import org.hibernate.internal.CoreMessageLogger;
+import org.hibernate.internal.util.NullnessUtil;
 
 import org.jboss.logging.Logger;
 
@@ -80,7 +81,7 @@ final class JndiServiceImpl implements JndiService {
 				}
 				else {
 					final String passThruPropertyName = propertyName.substring( Environment.JNDI_PREFIX.length() + 1 );
-					jndiProperties.put( passThruPropertyName, propertyValue );
+					jndiProperties.put( passThruPropertyName, NullnessUtil.castNonNull( propertyValue ) );
 				}
 			}
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AbstractJtaPlatform.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AbstractJtaPlatform.java
index ebd223045b..0d208c7eed 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AbstractJtaPlatform.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AbstractJtaPlatform.java
@@ -18,6 +18,7 @@ import org.hibernate.engine.jndi.spi.JndiService;
 import org.hibernate.engine.transaction.internal.jta.JtaStatusHelper;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatform;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformException;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.internal.util.config.ConfigurationHelper;
 import org.hibernate.service.ServiceRegistry;
 import org.hibernate.service.spi.Configurable;
@@ -63,7 +64,7 @@ public abstract class AbstractJtaPlatform
 	}
 
 	protected JndiService jndiService() {
-		return serviceRegistry().getService( JndiService.class );
+		return NullnessUtil.castNonNull( serviceRegistry().getService( JndiService.class ) );
 	}
 
 	protected abstract TransactionManager locateTransactionManager();
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AtomikosJtaPlatform.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AtomikosJtaPlatform.java
index 35b0e04ef7..1c09b386b7 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AtomikosJtaPlatform.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/AtomikosJtaPlatform.java
@@ -11,6 +11,7 @@ import jakarta.transaction.UserTransaction;
 
 import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformException;
+import org.hibernate.internal.util.NullnessUtil;
 
 /**
  * @author Vlad Mihalcea
@@ -21,7 +22,7 @@ public class AtomikosJtaPlatform extends AbstractJtaPlatform {
 	@Override
 	protected TransactionManager locateTransactionManager() {
 		try {
-			Class transactionManagerClass = serviceRegistry().getService( ClassLoaderService.class ).classForName( TM_CLASS_NAME );
+			Class transactionManagerClass = NullnessUtil.castNonNull( serviceRegistry().getService( ClassLoaderService.class ) ).classForName( TM_CLASS_NAME );
 			return  (TransactionManager) transactionManagerClass.newInstance();
 		}
 		catch (Exception e) {
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/BitronixJtaPlatform.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/BitronixJtaPlatform.java
index 2b9cd0baa6..be4e0aac95 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/BitronixJtaPlatform.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/BitronixJtaPlatform.java
@@ -12,6 +12,7 @@ import jakarta.transaction.UserTransaction;
 
 import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformException;
+import org.hibernate.internal.util.NullnessUtil;
 
 /**
  * @author Steve Ebersole
@@ -22,7 +23,7 @@ public class BitronixJtaPlatform extends AbstractJtaPlatform {
 	@Override
 	protected TransactionManager locateTransactionManager() {
 		try {
-			Class transactionManagerServicesClass = serviceRegistry().getService( ClassLoaderService.class ).classForName( TM_CLASS_NAME );
+			Class transactionManagerServicesClass = NullnessUtil.castNonNull( serviceRegistry().getService( ClassLoaderService.class ) ).classForName( TM_CLASS_NAME );
 			final Method getTransactionManagerMethod = transactionManagerServicesClass.getMethod( "getTransactionManager" );
 			return (TransactionManager) getTransactionManagerMethod.invoke( null );
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JBossStandAloneJtaPlatform.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JBossStandAloneJtaPlatform.java
index 85de78a5b2..46e525d3f5 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JBossStandAloneJtaPlatform.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JBossStandAloneJtaPlatform.java
@@ -11,6 +11,7 @@ import jakarta.transaction.UserTransaction;
 
 import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformException;
+import org.hibernate.internal.util.NullnessUtil;
 
 /**
  * Return a standalone JTA transaction manager for JBoss (Arjuna) Transactions or WildFly transaction client
@@ -37,8 +38,8 @@ public class JBossStandAloneJtaPlatform extends AbstractJtaPlatform {
 		}
 
 		try {
-			final Class jbossTmClass = serviceRegistry()
-					.getService( ClassLoaderService.class )
+			final Class jbossTmClass = NullnessUtil.castNonNull( serviceRegistry()
+					.getService( ClassLoaderService.class ) )
 					.classForName( JBOSS_TM_CLASS_NAME );
 			return (TransactionManager) jbossTmClass.getMethod( "transactionManager" ).invoke( null );
 		}
@@ -58,8 +59,8 @@ public class JBossStandAloneJtaPlatform extends AbstractJtaPlatform {
 		}
 
 		try {
-			final Class jbossUtClass = serviceRegistry()
-					.getService( ClassLoaderService.class )
+			final Class jbossUtClass = NullnessUtil.castNonNull( serviceRegistry()
+					.getService( ClassLoaderService.class ) )
 					.classForName( JBOSS_UT_CLASS_NAME );
 			return (UserTransaction) jbossUtClass.getMethod( "userTransaction" ).invoke( null );
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JOTMJtaPlatform.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JOTMJtaPlatform.java
index 8fa1ec33ee..0892b6bb45 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JOTMJtaPlatform.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JOTMJtaPlatform.java
@@ -12,6 +12,7 @@ import jakarta.transaction.UserTransaction;
 
 import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformException;
+import org.hibernate.internal.util.NullnessUtil;
 
 /**
  * @author Steve Ebersole
@@ -23,7 +24,7 @@ public class JOTMJtaPlatform extends AbstractJtaPlatform {
 	@Override
 	protected TransactionManager locateTransactionManager() {
 		try {
-			final Class tmClass = serviceRegistry().getService( ClassLoaderService.class ).classForName( TM_CLASS_NAME );
+			final Class tmClass = NullnessUtil.castNonNull( serviceRegistry().getService( ClassLoaderService.class ) ).classForName( TM_CLASS_NAME );
 			final Method getTransactionManagerMethod = tmClass.getMethod( "getTransactionManager" );
 			return (TransactionManager) getTransactionManagerMethod.invoke( null, (Object[]) null );
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformInitiator.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformInitiator.java
index e5abb95f9e..a74acd8ca7 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformInitiator.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformInitiator.java
@@ -14,6 +14,7 @@ import org.hibernate.cfg.AvailableSettings;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatform;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformResolver;
 import org.hibernate.internal.CoreMessageLogger;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 
 import org.jboss.logging.Logger;
@@ -38,11 +39,11 @@ public class JtaPlatformInitiator implements StandardServiceInitiator<JtaPlatfor
 	@Override
 	public @Nullable JtaPlatform initiateService(Map<String, Object> configurationValues, ServiceRegistryImplementor registry) {
 		final Object setting = configurationValues.get( AvailableSettings.JTA_PLATFORM );
-		JtaPlatform platform = registry.getService( StrategySelector.class ).resolveStrategy( JtaPlatform.class, setting );
+		JtaPlatform platform = NullnessUtil.castNonNull( registry.getService( StrategySelector.class ) ).resolveStrategy( JtaPlatform.class, setting );
 
 		if ( platform == null ) {
 			LOG.debug( "No JtaPlatform was specified, checking resolver" );
-			platform = registry.getService( JtaPlatformResolver.class ).resolveJtaPlatform( configurationValues, registry );
+			platform = NullnessUtil.castNonNull( registry.getService( JtaPlatformResolver.class ) ).resolveJtaPlatform( configurationValues, registry );
 		}
 
 		if ( platform == null ) {
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformResolverInitiator.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformResolverInitiator.java
index 4e7a0ad990..d340044934 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformResolverInitiator.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/JtaPlatformResolverInitiator.java
@@ -12,6 +12,7 @@ import org.hibernate.boot.registry.StandardServiceInitiator;
 import org.hibernate.boot.registry.selector.spi.StrategySelector;
 import org.hibernate.cfg.AvailableSettings;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformResolver;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 
 import org.jboss.logging.Logger;
@@ -27,7 +28,7 @@ public class JtaPlatformResolverInitiator implements StandardServiceInitiator<Jt
 	@Override
 	public JtaPlatformResolver initiateService(Map<String, Object> configurationValues, ServiceRegistryImplementor registry) {
 		final Object setting = configurationValues.get( AvailableSettings.JTA_PLATFORM_RESOLVER );
-		final JtaPlatformResolver resolver = registry.getService( StrategySelector.class )
+		final JtaPlatformResolver resolver = NullnessUtil.castNonNull( registry.getService( StrategySelector.class ) )
 				.resolveStrategy( JtaPlatformResolver.class, setting );
 		if ( resolver == null ) {
 			log.debugf( "No JtaPlatformResolver was specified, using default [%s]", StandardJtaPlatformResolver.class.getName() );
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/StandardJtaPlatformResolver.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/StandardJtaPlatformResolver.java
index df2ec1b85c..b916474f6d 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/StandardJtaPlatformResolver.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/StandardJtaPlatformResolver.java
@@ -13,6 +13,7 @@ import org.hibernate.boot.registry.classloading.spi.ClassLoadingException;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatform;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformProvider;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformResolver;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 
 import org.jboss.logging.Logger;
@@ -27,7 +28,7 @@ public class StandardJtaPlatformResolver implements JtaPlatformResolver {
 
 	@Override
 	public JtaPlatform resolveJtaPlatform(Map configurationValues, ServiceRegistryImplementor registry) {
-		final ClassLoaderService classLoaderService = registry.getService( ClassLoaderService.class );
+		final ClassLoaderService classLoaderService = NullnessUtil.castNonNull( registry.getService( ClassLoaderService.class ) );
 
 		// Initially look for a JtaPlatformProvider
 		for ( JtaPlatformProvider provider : classLoaderService.loadJavaServices( JtaPlatformProvider.class ) ) {
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WebSphereLibertyJtaPlatform.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WebSphereLibertyJtaPlatform.java
index 1237bcf5b9..ce6dc2b28f 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WebSphereLibertyJtaPlatform.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WebSphereLibertyJtaPlatform.java
@@ -34,8 +34,8 @@ public class WebSphereLibertyJtaPlatform extends AbstractJtaPlatform {
 	@Override
 	protected TransactionManager locateTransactionManager() {
 		try {
-			final Class<?> TransactionManagerFactory = serviceRegistry()
-					.getService( ClassLoaderService.class )
+			final Class<?> TransactionManagerFactory = NullnessUtil.castNonNull( serviceRegistry()
+					.getService( ClassLoaderService.class ) )
 					.classForName( TMF_CLASS_NAME );
 			return (TransactionManager) TransactionManagerFactory.getMethod("getTransactionManager").invoke(null);
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WildFlyStandAloneJtaPlatform.java b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WildFlyStandAloneJtaPlatform.java
index 2534b9f666..0067efa168 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WildFlyStandAloneJtaPlatform.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/transaction/jta/platform/internal/WildFlyStandAloneJtaPlatform.java
@@ -11,6 +11,7 @@ import jakarta.transaction.UserTransaction;
 
 import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatformException;
+import org.hibernate.internal.util.NullnessUtil;
 
 /**
  * Return a standalone JTA transaction manager for WildFly transaction client
@@ -25,8 +26,8 @@ public class WildFlyStandAloneJtaPlatform extends AbstractJtaPlatform {
 	@Override
 	protected TransactionManager locateTransactionManager() {
 		try {
-			final Class wildflyTmClass = serviceRegistry()
-					.getService( ClassLoaderService.class )
+			final Class wildflyTmClass = NullnessUtil.castNonNull( serviceRegistry()
+					.getService( ClassLoaderService.class ) )
 					.classForName( WILDFLY_TM_CLASS_NAME );
 			return (TransactionManager) wildflyTmClass.getMethod( "getInstance" ).invoke( null );
 		}
@@ -41,8 +42,8 @@ public class WildFlyStandAloneJtaPlatform extends AbstractJtaPlatform {
 	@Override
 	protected UserTransaction locateUserTransaction() {
 		try {
-			final Class jbossUtClass = serviceRegistry()
-					.getService( ClassLoaderService.class )
+			final Class jbossUtClass = NullnessUtil.castNonNull( serviceRegistry()
+					.getService( ClassLoaderService.class ) )
 					.classForName( WILDFLY_UT_CLASS_NAME );
 			return (UserTransaction) jbossUtClass.getMethod( "getInstance" ).invoke( null );
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/exception/ConstraintViolationException.java b/hibernate-core/src/main/java/org/hibernate/exception/ConstraintViolationException.java
index a7e0ab2587..111c3bb1ca 100644
--- a/hibernate-core/src/main/java/org/hibernate/exception/ConstraintViolationException.java
+++ b/hibernate-core/src/main/java/org/hibernate/exception/ConstraintViolationException.java
@@ -9,6 +9,8 @@ import java.sql.SQLException;
 
 import org.hibernate.JDBCException;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * A {@link JDBCException} indicating that the requested DML operation
  * resulted in violation of a defined integrity constraint.
@@ -17,14 +19,14 @@ import org.hibernate.JDBCException;
  */
 public class ConstraintViolationException extends JDBCException {
 
-	private final String constraintName;
+	private final @Nullable String constraintName;
 
-	public ConstraintViolationException(String message, SQLException root, String constraintName) {
+	public ConstraintViolationException(String message, SQLException root, @Nullable String constraintName) {
 		super( message, root );
 		this.constraintName = constraintName;
 	}
 
-	public ConstraintViolationException(String message, SQLException root, String sql, String constraintName) {
+	public ConstraintViolationException(String message, SQLException root, String sql, @Nullable String constraintName) {
 		super( message, root, sql );
 		this.constraintName = constraintName;
 	}
@@ -34,7 +36,7 @@ public class ConstraintViolationException extends JDBCException {
 	 *
 	 * @return The name of the violated constraint, or null if not known.
 	 */
-	public String getConstraintName() {
+	public @Nullable String getConstraintName() {
 		return constraintName;
 	}
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLExceptionTypeDelegate.java b/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLExceptionTypeDelegate.java
index 803d9fbbfd..b3cae2ff7a 100644
--- a/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLExceptionTypeDelegate.java
+++ b/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLExceptionTypeDelegate.java
@@ -28,6 +28,8 @@ import org.hibernate.exception.SQLGrammarException;
 import org.hibernate.exception.spi.AbstractSQLExceptionConversionDelegate;
 import org.hibernate.exception.spi.ConversionContext;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * A {@link org.hibernate.exception.spi.SQLExceptionConverter} implementation
  * that does conversion based on the {@link SQLException} subtype hierarchy
@@ -41,7 +43,7 @@ public class SQLExceptionTypeDelegate extends AbstractSQLExceptionConversionDele
 	}
 
 	@Override
-	public JDBCException convert(SQLException sqlException, String message, String sql) {
+	public @Nullable JDBCException convert(SQLException sqlException, String message, String sql) {
 		if ( sqlException instanceof SQLClientInfoException
 				|| sqlException instanceof SQLInvalidAuthorizationSpecException
 				|| sqlException instanceof SQLNonTransientConnectionException
diff --git a/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLStateConversionDelegate.java b/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLStateConversionDelegate.java
index 3e869900ce..331492ea03 100644
--- a/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLStateConversionDelegate.java
+++ b/hibernate-core/src/main/java/org/hibernate/exception/internal/SQLStateConversionDelegate.java
@@ -21,6 +21,8 @@ import org.hibernate.exception.spi.AbstractSQLExceptionConversionDelegate;
 import org.hibernate.exception.spi.ConversionContext;
 import org.hibernate.internal.util.JdbcExceptionHelper;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * A {@link org.hibernate.exception.spi.SQLExceptionConverter} implementation which performs conversion based
  * on the underlying SQLState. Interpretation of a SQL error based on SQLState is not nearly as accurate as
@@ -77,7 +79,7 @@ public class SQLStateConversionDelegate extends AbstractSQLExceptionConversionDe
 	}
 
 	@Override
-	public JDBCException convert(SQLException sqlException, String message, String sql) {
+	public @Nullable JDBCException convert(SQLException sqlException, String message, String sql) {
 		final String sqlState = JdbcExceptionHelper.extractSqlState( sqlException );
 		final int errorCode = JdbcExceptionHelper.extractErrorCode( sqlException );
 
diff --git a/hibernate-core/src/main/java/org/hibernate/exception/internal/StandardSQLExceptionConverter.java b/hibernate-core/src/main/java/org/hibernate/exception/internal/StandardSQLExceptionConverter.java
index 055b8e42c6..e3b5f91f03 100644
--- a/hibernate-core/src/main/java/org/hibernate/exception/internal/StandardSQLExceptionConverter.java
+++ b/hibernate-core/src/main/java/org/hibernate/exception/internal/StandardSQLExceptionConverter.java
@@ -16,6 +16,8 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * A {@link SQLExceptionConverter} that delegates to a chain of
  * {@link SQLExceptionConversionDelegate}.
@@ -44,7 +46,7 @@ public class StandardSQLExceptionConverter implements SQLExceptionConverter {
 	 * @deprecated use {@link #StandardSQLExceptionConverter(SQLExceptionConversionDelegate...)}
 	 */
 	@Deprecated(since = "6.0")
-	public void addDelegate(SQLExceptionConversionDelegate delegate) {
+	public void addDelegate(@Nullable SQLExceptionConversionDelegate delegate) {
 		if ( delegate != null ) {
 			this.delegates.add( delegate );
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/exception/spi/SQLExceptionConversionDelegate.java b/hibernate-core/src/main/java/org/hibernate/exception/spi/SQLExceptionConversionDelegate.java
index 5d20e58196..59a98d5f6f 100644
--- a/hibernate-core/src/main/java/org/hibernate/exception/spi/SQLExceptionConversionDelegate.java
+++ b/hibernate-core/src/main/java/org/hibernate/exception/spi/SQLExceptionConversionDelegate.java
@@ -10,6 +10,8 @@ import java.sql.SQLException;
 
 import org.hibernate.JDBCException;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Allow a {@link SQLExceptionConverter} to work by chaining together
  * multiple delegates. The main difference between a delegate and a
@@ -31,6 +33,6 @@ public interface SQLExceptionConversionDelegate {
 	 *         if this delegate does not know how to interpret the
 	 *         given {@link SQLException}.
 	 */
-	JDBCException convert(SQLException sqlException, String message, String sql);
+	@Nullable JDBCException convert(SQLException sqlException, String message, String sql);
 
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/exception/spi/TemplatedViolatedConstraintNameExtractor.java b/hibernate-core/src/main/java/org/hibernate/exception/spi/TemplatedViolatedConstraintNameExtractor.java
index c032cef912..89b4e805f8 100644
--- a/hibernate-core/src/main/java/org/hibernate/exception/spi/TemplatedViolatedConstraintNameExtractor.java
+++ b/hibernate-core/src/main/java/org/hibernate/exception/spi/TemplatedViolatedConstraintNameExtractor.java
@@ -9,6 +9,10 @@ package org.hibernate.exception.spi;
 import java.sql.SQLException;
 import java.util.function.Function;
 
+import org.hibernate.internal.util.NullnessUtil;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Extracts a violated database constraint name from an error message
  * by matching the error message against a template.
@@ -25,7 +29,7 @@ public class TemplatedViolatedConstraintNameExtractor implements ViolatedConstra
 	}
 
 	@Override
-	public String extractConstraintName(SQLException sqle) {
+	public @Nullable String extractConstraintName(SQLException sqle) {
 		try {
 			String constraintName = null;
 
@@ -37,7 +41,7 @@ public class TemplatedViolatedConstraintNameExtractor implements ViolatedConstra
 					break;
 				}
 				else {
-					sqle = sqle.getNextException();
+					sqle = NullnessUtil.castNonNull( sqle.getNextException() );
 				}
 			} while (constraintName == null);
 
@@ -57,7 +61,7 @@ public class TemplatedViolatedConstraintNameExtractor implements ViolatedConstra
 	 * @param message       The templated error message containing the constraint name.
 	 * @return The found constraint name, or null.
 	 */
-	public static String extractUsingTemplate(String templateStart, String templateEnd, String message) {
+	public static @Nullable String extractUsingTemplate(String templateStart, String templateEnd, String message) {
 		int templateStartPosition = message.indexOf( templateStart );
 		if ( templateStartPosition < 0 ) {
 			return null;
diff --git a/hibernate-core/src/main/java/org/hibernate/exception/spi/ViolatedConstraintNameExtractor.java b/hibernate-core/src/main/java/org/hibernate/exception/spi/ViolatedConstraintNameExtractor.java
index 3e1abd222d..f99dda5233 100644
--- a/hibernate-core/src/main/java/org/hibernate/exception/spi/ViolatedConstraintNameExtractor.java
+++ b/hibernate-core/src/main/java/org/hibernate/exception/spi/ViolatedConstraintNameExtractor.java
@@ -8,6 +8,8 @@ package org.hibernate.exception.spi;
 
 import java.sql.SQLException;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * An object that can extract the name of a violated database constraint
  * from a {@link SQLException} that results from the constraint violation.
@@ -23,5 +25,5 @@ public interface ViolatedConstraintNameExtractor {
 	 * @param sqle The exception that was the result of the constraint violation.
 	 * @return The extracted constraint name.
 	 */
-	String extractConstraintName(SQLException sqle);
+	@Nullable String extractConstraintName(SQLException sqle);
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/id/SequenceMismatchStrategy.java b/hibernate-core/src/main/java/org/hibernate/id/SequenceMismatchStrategy.java
index ec351966ee..80a58a368c 100644
--- a/hibernate-core/src/main/java/org/hibernate/id/SequenceMismatchStrategy.java
+++ b/hibernate-core/src/main/java/org/hibernate/id/SequenceMismatchStrategy.java
@@ -8,6 +8,8 @@ package org.hibernate.id;
 
 import org.hibernate.HibernateException;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Describes the strategy for handling the mismatch between a database sequence configuration and
  * the one defined by the entity mapping.
@@ -53,7 +55,7 @@ public enum SequenceMismatchStrategy {
 	 *
 	 * @return associated {@link SequenceMismatchStrategy} object
 	 */
-	public static SequenceMismatchStrategy interpret(Object sequenceMismatchStrategy) {
+	public static SequenceMismatchStrategy interpret(@Nullable Object sequenceMismatchStrategy) {
 		if ( sequenceMismatchStrategy == null ) {
 			return EXCEPTION;
 		}
diff --git a/hibernate-core/src/main/java/org/hibernate/integrator/internal/IntegratorServiceImpl.java b/hibernate-core/src/main/java/org/hibernate/integrator/internal/IntegratorServiceImpl.java
index 258464bc24..711a3fb6bd 100644
--- a/hibernate-core/src/main/java/org/hibernate/integrator/internal/IntegratorServiceImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/integrator/internal/IntegratorServiceImpl.java
@@ -24,20 +24,26 @@ public class IntegratorServiceImpl implements IntegratorService {
 
 	private final LinkedHashSet<Integrator> integrators = new LinkedHashSet<>();
 
-	public IntegratorServiceImpl(LinkedHashSet<Integrator> providedIntegrators, ClassLoaderService classLoaderService) {
+	private IntegratorServiceImpl() {
+	}
+
+	public static IntegratorServiceImpl create(LinkedHashSet<Integrator> providedIntegrators, ClassLoaderService classLoaderService) {
+		IntegratorServiceImpl instance = new IntegratorServiceImpl();
+
 		// register standard integrators.  Envers and JPA, for example, need to be handled by discovery because in
 		// separate project/jars.
-		addIntegrator( new BeanValidationIntegrator() );
-		addIntegrator( new CollectionCacheInvalidator() );
+		instance.addIntegrator( new BeanValidationIntegrator() );
+		instance.addIntegrator( new CollectionCacheInvalidator() );
 
 		// register provided integrators
 		for ( Integrator integrator : providedIntegrators ) {
-			addIntegrator( integrator );
+			instance.addIntegrator( integrator );
+		}
+		for ( Integrator integrator : classLoaderService.loadJavaServices( Integrator.class ) ) {
+			instance.addIntegrator( integrator );
 		}
 
-		for ( Integrator integrator : classLoaderService.loadJavaServices( Integrator.class ) ) {
-			addIntegrator( integrator );
-		}
+		return instance;
 	}
 
 	private void addIntegrator(Integrator integrator) {
diff --git a/hibernate-core/src/main/java/org/hibernate/internal/util/config/ConfigurationHelper.java b/hibernate-core/src/main/java/org/hibernate/internal/util/config/ConfigurationHelper.java
index 25999e012b..979a52271c 100644
--- a/hibernate-core/src/main/java/org/hibernate/internal/util/config/ConfigurationHelper.java
+++ b/hibernate-core/src/main/java/org/hibernate/internal/util/config/ConfigurationHelper.java
@@ -592,10 +592,6 @@ public final class ConfigurationHelper {
 
 		@Override
 		public Integer convert(Object value) {
-			if ( value == null ) {
-				throw new IllegalArgumentException( "Null value passed to convert" );
-			}
-
 			if ( value instanceof Number ) {
 				return ( (Number) value ).intValue();
 			}
diff --git a/hibernate-core/src/main/java/org/hibernate/service/ServiceRegistry.java b/hibernate-core/src/main/java/org/hibernate/service/ServiceRegistry.java
index 1f4b082d8b..e8afded73f 100644
--- a/hibernate-core/src/main/java/org/hibernate/service/ServiceRegistry.java
+++ b/hibernate-core/src/main/java/org/hibernate/service/ServiceRegistry.java
@@ -6,6 +6,8 @@
  */
 package org.hibernate.service;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * A registry of {@linkplain Service services}. This interface abstracts
  * the operations of:
@@ -27,7 +29,7 @@ public interface ServiceRegistry extends AutoCloseable {
 	 * 
 	 * @return The parent registry.  May be null.
 	 */
-	ServiceRegistry getParentServiceRegistry();
+	@Nullable ServiceRegistry getParentServiceRegistry();
 
 	/**
 	 * Retrieve a service by role.  If service is not found, but a {@link org.hibernate.service.spi.ServiceInitiator} is
@@ -42,7 +44,7 @@ public interface ServiceRegistry extends AutoCloseable {
 	 *
 	 * @throws UnknownServiceException Indicates the service was not known.
 	 */
-	<R extends Service> R getService(Class<R> serviceRole);
+	<R extends Service> @Nullable R getService(Class<R> serviceRole);
 
 	/**
 	 * Retrieve a service by role.  If service is not found, but a {@link org.hibernate.service.spi.ServiceInitiator} is
diff --git a/hibernate-core/src/main/java/org/hibernate/service/internal/AbstractServiceRegistryImpl.java b/hibernate-core/src/main/java/org/hibernate/service/internal/AbstractServiceRegistryImpl.java
index 563f520717..aaca3c5ac1 100644
--- a/hibernate-core/src/main/java/org/hibernate/service/internal/AbstractServiceRegistryImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/service/internal/AbstractServiceRegistryImpl.java
@@ -35,6 +35,8 @@ import org.hibernate.service.spi.ServiceRegistryImplementor;
 import org.hibernate.service.spi.Startable;
 import org.hibernate.service.spi.Stoppable;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Basic implementation of the {@link ServiceRegistry} and {@link ServiceRegistryImplementor} contracts.
  *
@@ -48,7 +50,7 @@ public abstract class AbstractServiceRegistryImpl
 
 	public static final String ALLOW_CRAWLING = "hibernate.service.allow_crawling";
 
-	private volatile ServiceRegistryImplementor parent;
+	private volatile @Nullable ServiceRegistryImplementor parent;
 	private final boolean allowCrawling;
 
 	private final ConcurrentMap<Class<?>,ServiceBinding<?>> serviceBindingMap = new ConcurrentHashMap<>();
@@ -70,26 +72,17 @@ public abstract class AbstractServiceRegistryImpl
 
 	private final AtomicBoolean active = new AtomicBoolean( true );
 
-	protected AbstractServiceRegistryImpl() {
-		this( (ServiceRegistryImplementor) null );
-	}
-
-	protected AbstractServiceRegistryImpl(boolean autoCloseRegistry) {
-		this( (ServiceRegistryImplementor) null, autoCloseRegistry );
-	}
-
-	protected AbstractServiceRegistryImpl(ServiceRegistryImplementor parent) {
+	protected AbstractServiceRegistryImpl(@Nullable ServiceRegistryImplementor parent) {
 		this( parent, true );
 	}
 
 	protected AbstractServiceRegistryImpl(
-			ServiceRegistryImplementor parent,
+			@Nullable ServiceRegistryImplementor parent,
 			boolean autoCloseRegistry) {
+
 		this.parent = parent;
 		this.allowCrawling = ConfigurationHelper.getBoolean( ALLOW_CRAWLING, Environment.getProperties(), true );
-
 		this.autoCloseRegistry = autoCloseRegistry;
-		this.parent.registerChild( this );
 	}
 
 	public AbstractServiceRegistryImpl(BootstrapServiceRegistry bootstrapServiceRegistry) {
@@ -99,14 +92,20 @@ public abstract class AbstractServiceRegistryImpl
 	public AbstractServiceRegistryImpl(
 			BootstrapServiceRegistry bootstrapServiceRegistry,
 			boolean autoCloseRegistry) {
+
 		if ( !(bootstrapServiceRegistry instanceof ServiceRegistryImplementor) ) {
 			throw new IllegalArgumentException( "ServiceRegistry parent needs to implement ServiceRegistryImplementor" );
 		}
 		this.parent = (ServiceRegistryImplementor) bootstrapServiceRegistry;
 		this.allowCrawling = ConfigurationHelper.getBoolean( ALLOW_CRAWLING, Environment.getProperties(), true );
-
 		this.autoCloseRegistry = autoCloseRegistry;
-		this.parent.registerChild( this );
+	}
+
+	// For nullness checking purposes
+	protected void initialize() {
+		if ( this.parent != null ) {
+			this.parent.registerChild( this );
+		}
 	}
 
 	protected <R extends Service> void createServiceBinding(ServiceInitiator<R> initiator) {
@@ -128,17 +127,17 @@ public abstract class AbstractServiceRegistryImpl
 	}
 
 	@Override
-	public ServiceRegistry getParentServiceRegistry() {
+	public @Nullable ServiceRegistry getParentServiceRegistry() {
 		return parent;
 	}
 
 	@Override
-	public <R extends Service> ServiceBinding<R> locateServiceBinding(Class<R> serviceRole) {
+	public <R extends Service> @Nullable ServiceBinding<R> locateServiceBinding(Class<R> serviceRole) {
 		return locateServiceBinding( serviceRole, true );
 	}
 
 	@SuppressWarnings("unchecked")
-	protected <R extends Service> ServiceBinding<R> locateServiceBinding(Class<R> serviceRole, boolean checkParent) {
+	protected <R extends Service> @Nullable ServiceBinding<R> locateServiceBinding(Class<R> serviceRole, boolean checkParent) {
 		ServiceBinding<R> serviceBinding = (ServiceBinding<R>) serviceBindingMap.get( serviceRole );
 		if ( serviceBinding == null && checkParent && parent != null ) {
 			// look in parent
@@ -184,7 +183,7 @@ public abstract class AbstractServiceRegistryImpl
 	}
 
 	@Override
-	public <R extends Service> R getService(Class<R> serviceRole) {
+	public <R extends Service> @Nullable R getService(Class<R> serviceRole) {
 		//Fast-path for ClassLoaderService as it's extremely hot during bootstrap
 		//(and after bootstrap service loading performance is less interesting as it's
 		//ideally being cached by long term consumers)
@@ -230,7 +229,7 @@ public abstract class AbstractServiceRegistryImpl
 		}
 	}
 
-	private <R extends Service> R initializeService(ServiceBinding<R> serviceBinding) {
+	private <R extends Service> @Nullable R initializeService(ServiceBinding<R> serviceBinding) {
 		if ( log.isTraceEnabled() ) {
 			log.tracev( "Initializing service [role={0}]", serviceBinding.getServiceRole().getName() );
 		}
@@ -253,7 +252,7 @@ public abstract class AbstractServiceRegistryImpl
 		return service;
 	}
 
-	protected <R extends Service> R createService(ServiceBinding<R> serviceBinding) {
+	protected <R extends Service> @Nullable R createService(ServiceBinding<R> serviceBinding) {
 		final ServiceInitiator<R> serviceInitiator = serviceBinding.getServiceInitiator();
 		if ( serviceInitiator == null ) {
 			// this condition should never ever occur
@@ -371,7 +370,9 @@ public abstract class AbstractServiceRegistryImpl
 				serviceBindingMap.clear();
 			}
 			finally {
-				parent.deRegisterChild( this );
+				if ( parent != null ) {
+					parent.deRegisterChild( this );
+				}
 			}
 		}
 	}
@@ -429,7 +430,7 @@ public abstract class AbstractServiceRegistryImpl
 	 * Not intended for general use. We need the ability to stop and "reactivate" a registry to allow
 	 * experimentation with technologies such as GraalVM, Quarkus and Cri-O.
 	 */
-	public synchronized void resetParent(BootstrapServiceRegistry newParent) {
+	public synchronized void resetParent(@Nullable BootstrapServiceRegistry newParent) {
 		if ( this.parent != null ) {
 			this.parent.deRegisterChild( this );
 		}
@@ -446,14 +447,14 @@ public abstract class AbstractServiceRegistryImpl
 	}
 
 	@Override
-	public <T extends Service> T fromRegistryOrChildren(Class<T> serviceRole) {
+	public <T extends Service> @Nullable T fromRegistryOrChildren(Class<T> serviceRole) {
 		return fromRegistryOrChildren( serviceRole, this, childRegistries );
 	}
 
-	public static <T extends Service> T fromRegistryOrChildren(
+	public static <T extends Service> @Nullable T fromRegistryOrChildren(
 			Class<T> serviceRole,
 			ServiceRegistryImplementor serviceRegistry,
-			Set<ServiceRegistryImplementor> childRegistries) {
+			@Nullable Set<ServiceRegistryImplementor> childRegistries) {
 		// prefer `serviceRegistry`
 		final T localService = serviceRegistry.getService( serviceRole );
 		if ( localService != null ) {
diff --git a/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryBuilderImpl.java b/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryBuilderImpl.java
index 22628e7ddc..be1a183f00 100644
--- a/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryBuilderImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryBuilderImpl.java
@@ -60,7 +60,7 @@ public class SessionFactoryServiceRegistryBuilderImpl implements SessionFactoryS
 	public SessionFactoryServiceRegistry buildSessionFactoryServiceRegistry(
 			SessionFactoryImplementor sessionFactory,
 			SessionFactoryOptions options) {
-		return new SessionFactoryServiceRegistryImpl(
+		return SessionFactoryServiceRegistryImpl.create(
 				parent,
 				initiators,
 				providedServices,
diff --git a/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryFactoryImpl.java b/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryFactoryImpl.java
index a9cc421b6e..3ac9a702d7 100644
--- a/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryFactoryImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryFactoryImpl.java
@@ -9,6 +9,7 @@ package org.hibernate.service.internal;
 import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.boot.spi.SessionFactoryOptions;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 import org.hibernate.service.spi.SessionFactoryServiceContributor;
 import org.hibernate.service.spi.SessionFactoryServiceRegistry;
@@ -31,7 +32,7 @@ public class SessionFactoryServiceRegistryFactoryImpl implements SessionFactoryS
 	public SessionFactoryServiceRegistry buildServiceRegistry(
 			SessionFactoryImplementor sessionFactory,
 			SessionFactoryOptions options) {
-		final ClassLoaderService cls = options.getServiceRegistry().getService( ClassLoaderService.class );
+		final ClassLoaderService cls = NullnessUtil.castNonNull( options.getServiceRegistry().getService( ClassLoaderService.class ) );
 		final SessionFactoryServiceRegistryBuilderImpl builder = new SessionFactoryServiceRegistryBuilderImpl( theBasicServiceRegistry );
 
 		for ( SessionFactoryServiceContributor contributor : cls.loadJavaServices( SessionFactoryServiceContributor.class ) ) {
diff --git a/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryImpl.java b/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryImpl.java
index 21f0063c6d..922331361f 100644
--- a/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/service/internal/SessionFactoryServiceRegistryImpl.java
@@ -12,6 +12,7 @@ import org.hibernate.boot.spi.SessionFactoryOptions;
 import org.hibernate.engine.config.spi.ConfigurationService;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.event.service.spi.EventListenerRegistry;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.service.Service;
 import org.hibernate.service.spi.Configurable;
 import org.hibernate.service.spi.ServiceBinding;
@@ -23,6 +24,8 @@ import org.hibernate.service.spi.SessionFactoryServiceRegistry;
 
 import org.jboss.logging.Logger;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * @author Steve Ebersole
  */
@@ -35,17 +38,28 @@ public class SessionFactoryServiceRegistryImpl
 	private final SessionFactoryOptions sessionFactoryOptions;
 	private final SessionFactoryImplementor sessionFactory;
 
-	public SessionFactoryServiceRegistryImpl(
+	private SessionFactoryServiceRegistryImpl(
+			ServiceRegistryImplementor parent,
+			SessionFactoryImplementor sessionFactory,
+			SessionFactoryOptions sessionFactoryOptions) {
+		super( parent );
+		this.sessionFactory = sessionFactory;
+		this.sessionFactoryOptions = sessionFactoryOptions;
+	}
+
+	public static SessionFactoryServiceRegistryImpl create(
 			ServiceRegistryImplementor parent,
 			List<SessionFactoryServiceInitiator<?>> initiators,
 			List<ProvidedService<?>> providedServices,
 			SessionFactoryImplementor sessionFactory,
 			SessionFactoryOptions sessionFactoryOptions) {
-		super( parent );
-
-		this.sessionFactory = sessionFactory;
-		this.sessionFactoryOptions = sessionFactoryOptions;
+		SessionFactoryServiceRegistryImpl instance = new SessionFactoryServiceRegistryImpl( parent, sessionFactory, sessionFactoryOptions);
+		instance.initialize( initiators, providedServices );
+		return instance;
+	}
 
+	protected void initialize(List<SessionFactoryServiceInitiator<?>> initiators, List<ProvidedService<?>> providedServices) {
+		super.initialize();
 		// for now, just use the standard initiator list
 		for ( SessionFactoryServiceInitiator<?> initiator : initiators ) {
 			// create the bindings up front to help identify to which registry services belong
@@ -66,7 +80,7 @@ public class SessionFactoryServiceRegistryImpl
 	@Override
 	public <R extends Service> void configureService(ServiceBinding<R> serviceBinding) {
 		if ( serviceBinding.getService() instanceof Configurable ) {
-			( (Configurable) serviceBinding.getService() ).configure( getService( ConfigurationService.class ).getSettings() );
+			( (Configurable) serviceBinding.getService() ).configure( NullnessUtil.castNonNull( getService( ConfigurationService.class ) ).getSettings() );
 		}
 	}
 
@@ -86,7 +100,7 @@ public class SessionFactoryServiceRegistryImpl
 	}
 
 	@Override
-	public <R extends Service> R getService(Class<R> serviceRole) {
+	public <R extends Service> @Nullable R getService(Class<R> serviceRole) {
 		if ( serviceRole.equals( EventListenerRegistry.class ) ) {
 			log.debug(
 					"EventListenerRegistry access via ServiceRegistry is deprecated.  " +
diff --git a/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceBinding.java b/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceBinding.java
index 9fcb4243e7..0afb4f46b8 100644
--- a/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceBinding.java
+++ b/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceBinding.java
@@ -10,6 +10,8 @@ import org.hibernate.service.Service;
 
 import org.jboss.logging.Logger;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Models a binding for a particular service.
  *
@@ -30,7 +32,7 @@ public final class ServiceBinding<R extends Service> {
 
 	private final ServiceLifecycleOwner lifecycleOwner;
 	private final Class<R> serviceRole;
-	private final ServiceInitiator<R> serviceInitiator;
+	private final @Nullable ServiceInitiator<R> serviceInitiator;
 	private volatile R service;
 
 	public ServiceBinding(ServiceLifecycleOwner lifecycleOwner, Class<R> serviceRole, R service) {
@@ -54,7 +56,7 @@ public final class ServiceBinding<R extends Service> {
 		return serviceRole;
 	}
 
-	public ServiceInitiator<R> getServiceInitiator() {
+	public @Nullable ServiceInitiator<R> getServiceInitiator() {
 		return serviceInitiator;
 	}
 
diff --git a/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceRegistryImplementor.java b/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceRegistryImplementor.java
index 023bef2f04..9e819021d6 100644
--- a/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceRegistryImplementor.java
+++ b/hibernate-core/src/main/java/org/hibernate/service/spi/ServiceRegistryImplementor.java
@@ -9,6 +9,8 @@ package org.hibernate.service.spi;
 import org.hibernate.service.Service;
 import org.hibernate.service.ServiceRegistry;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Additional integration contracts for a service registry.
  *
@@ -23,7 +25,7 @@ public interface ServiceRegistryImplementor extends ServiceRegistry {
 	 *
 	 * @return The located binding; may be {@code null}
 	 */
-	<R extends Service> ServiceBinding<R> locateServiceBinding(Class<R> serviceRole);
+	<R extends Service> @Nullable ServiceBinding<R> locateServiceBinding(Class<R> serviceRole);
 
 	@Override
 	default void close() {
@@ -47,5 +49,5 @@ public interface ServiceRegistryImplementor extends ServiceRegistry {
 	 */
 	void deRegisterChild(ServiceRegistryImplementor child);
 
-	<T extends Service> T fromRegistryOrChildren(Class<T> serviceRole);
+	<T extends Service> @Nullable T fromRegistryOrChildren(Class<T> serviceRole);
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/stat/internal/StatisticsInitiator.java b/hibernate-core/src/main/java/org/hibernate/stat/internal/StatisticsInitiator.java
index f4289d205b..ec46819dc2 100644
--- a/hibernate-core/src/main/java/org/hibernate/stat/internal/StatisticsInitiator.java
+++ b/hibernate-core/src/main/java/org/hibernate/stat/internal/StatisticsInitiator.java
@@ -11,6 +11,7 @@ import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
 import org.hibernate.engine.config.spi.ConfigurationService;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.internal.CoreMessageLogger;
+import org.hibernate.internal.util.NullnessUtil;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 import org.hibernate.service.spi.SessionFactoryServiceInitiator;
 import org.hibernate.service.spi.SessionFactoryServiceInitiatorContext;
@@ -42,8 +43,8 @@ public class StatisticsInitiator implements SessionFactoryServiceInitiator<Stati
 
 	@Override
 	public StatisticsImplementor initiateService(SessionFactoryServiceInitiatorContext context) {
-		final Object configValue = context.getServiceRegistry()
-				.getService( ConfigurationService.class )
+		final Object configValue = NullnessUtil.castNonNull( context.getServiceRegistry()
+				.getService( ConfigurationService.class ) )
 				.getSettings()
 				.get( STATS_BUILDER );
 		return initiateServiceInternal( context.getSessionFactory(), configValue, context.getServiceRegistry() );
@@ -63,7 +64,7 @@ public class StatisticsInitiator implements SessionFactoryServiceInitiator<Stati
 		}
 		else {
 			// assume it names the factory class
-			final ClassLoaderService classLoaderService = registry.getService( ClassLoaderService.class );
+			final ClassLoaderService classLoaderService = NullnessUtil.castNonNull( registry.getService( ClassLoaderService.class ) );
 			try {
 				statisticsFactory = (StatisticsFactory) classLoaderService.classForName( configValue.toString() ).newInstance();
 			}
diff --git a/hibernate-core/src/main/java/org/hibernate/type/WrapperArrayHandling.java b/hibernate-core/src/main/java/org/hibernate/type/WrapperArrayHandling.java
index 6f47e7caaa..38b1e95df0 100644
--- a/hibernate-core/src/main/java/org/hibernate/type/WrapperArrayHandling.java
+++ b/hibernate-core/src/main/java/org/hibernate/type/WrapperArrayHandling.java
@@ -12,6 +12,8 @@ import org.hibernate.cfg.AvailableSettings;
 import org.hibernate.type.descriptor.java.ByteArrayJavaType;
 import org.hibernate.type.descriptor.java.CharacterArrayJavaType;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Possible options for how to handle {@code Byte[]} and {@code Character[]} basic mappings
  * encountered in the application domain model.
@@ -70,7 +72,7 @@ public enum WrapperArrayHandling {
 	 * Form of {@link #interpretExternalSetting(Object)} which allows incoming {@code null} values and
 	 * simply returns {@code null}.  Useful for chained resolutions
 	 */
-	public static WrapperArrayHandling interpretExternalSettingLeniently(Object value) {
+	public static WrapperArrayHandling interpretExternalSettingLeniently(@Nullable Object value) {
 		if ( value == null ) {
 			return null;
 		}
diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/connection/ConnectionCreatorTest.java b/hibernate-core/src/test/java/org/hibernate/orm/test/connection/ConnectionCreatorTest.java
index be0a3f66a9..8ef09471f9 100644
--- a/hibernate-core/src/test/java/org/hibernate/orm/test/connection/ConnectionCreatorTest.java
+++ b/hibernate-core/src/test/java/org/hibernate/orm/test/connection/ConnectionCreatorTest.java
@@ -9,8 +9,11 @@ package org.hibernate.orm.test.connection;
 import java.sql.Connection;
 import java.sql.Driver;
 import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
+import org.hibernate.boot.registry.BootstrapServiceRegistry;
 import org.hibernate.boot.registry.StandardServiceInitiator;
 import org.hibernate.boot.registry.internal.BootstrapServiceRegistryImpl;
 import org.hibernate.boot.registry.internal.StandardServiceRegistryImpl;
@@ -20,9 +23,9 @@ import org.hibernate.engine.jdbc.spi.JdbcServices;
 import org.hibernate.exception.JDBCConnectionException;
 import org.hibernate.service.Service;
 import org.hibernate.service.internal.ProvidedService;
-
-import org.hibernate.testing.TestForIssue;
 import org.hibernate.testing.junit4.BaseUnitTestCase;
+import org.hibernate.testing.orm.junit.JiraKey;
+
 import org.junit.Test;
 
 import static org.junit.Assert.fail;
@@ -32,27 +35,17 @@ import static org.junit.Assert.fail;
  */
 public class ConnectionCreatorTest extends BaseUnitTestCase {
 	@Test
-	@TestForIssue( jiraKey = "HHH-8621" )
+	@JiraKey(value = "HHH-8621" )
 	public void testBadUrl() throws Exception {
 		DriverConnectionCreator connectionCreator = new DriverConnectionCreator(
 				(Driver) Class.forName( "org.h2.Driver" ).newInstance(),
-				new StandardServiceRegistryImpl(
+				CCTStandardServiceRegistryImpl.create(
 						true,
 						new BootstrapServiceRegistryImpl(),
 						Collections.emptyList(),
 						Collections.emptyList(),
 						Collections.emptyMap()
-				) {
-					@Override
-					@SuppressWarnings("unchecked")
-					public <R extends Service> R getService(Class<R> serviceRole) {
-						if ( JdbcServices.class.equals( serviceRole ) ) {
-							// return a new, not fully initialized JdbcServicesImpl
-							return (R) new JdbcServicesImpl();
-						}
-						return super.getService( serviceRole );
-					}
-				},
+				),
 				"jdbc:h2:mem:test-bad-urls;nosuchparam=saywhat",
 				new Properties(),
 				false,
@@ -68,4 +61,37 @@ public class ConnectionCreatorTest extends BaseUnitTestCase {
 		catch (JDBCConnectionException expected) {
 		}
 	}
+
+	private final static class CCTStandardServiceRegistryImpl extends StandardServiceRegistryImpl {
+
+		private CCTStandardServiceRegistryImpl(
+				boolean autoCloseRegistry,
+				BootstrapServiceRegistry bootstrapServiceRegistry,
+				Map<String, Object> configurationValues) {
+			super( autoCloseRegistry, bootstrapServiceRegistry, configurationValues );
+		}
+		@Override
+		@SuppressWarnings("unchecked")
+		public <R extends Service> R getService(Class<R> serviceRole) {
+			if ( JdbcServices.class.equals( serviceRole ) ) {
+				// return a new, not fully initialized JdbcServicesImpl
+				return (R) new JdbcServicesImpl();
+			}
+			return super.getService( serviceRole );
+		}
+
+		public static CCTStandardServiceRegistryImpl create(
+				boolean autoCloseRegistry,
+				BootstrapServiceRegistry bootstrapServiceRegistry,
+				List<StandardServiceInitiator<?>> serviceInitiators,
+				List<ProvidedService<?>> providedServices,
+				Map<String,Object> configurationValues) {
+
+			CCTStandardServiceRegistryImpl instance = new CCTStandardServiceRegistryImpl( autoCloseRegistry, bootstrapServiceRegistry, configurationValues );
+			instance.initialize();
+			instance.applyServiceRegistrations( serviceInitiators, providedServices );
+
+			return instance;
+		}
+	}
 }
diff --git a/hibernate-micrometer/src/main/java/org/hibernate/stat/HibernateQueryMetrics.java b/hibernate-micrometer/src/main/java/org/hibernate/stat/HibernateQueryMetrics.java
index 21f9687cb0..1480b75904 100644
--- a/hibernate-micrometer/src/main/java/org/hibernate/stat/HibernateQueryMetrics.java
+++ b/hibernate-micrometer/src/main/java/org/hibernate/stat/HibernateQueryMetrics.java
@@ -85,8 +85,7 @@ public class HibernateQueryMetrics implements MeterBinder {
 	@Override
 	public void bindTo(MeterRegistry meterRegistry) {
 		if ( sessionFactory instanceof SessionFactoryImplementor ) {
-			EventListenerRegistry eventListenerRegistry = ( (SessionFactoryImplementor) sessionFactory ).getServiceRegistry()
-					.getService( EventListenerRegistry.class );
+			EventListenerRegistry eventListenerRegistry = ( (SessionFactoryImplementor) sessionFactory ).getEventEngine().getListenerRegistry();
 			MetricsEventHandler metricsEventHandler = new MetricsEventHandler( meterRegistry );
 			eventListenerRegistry.appendListeners( EventType.POST_LOAD, metricsEventHandler );
 		}
diff --git a/hibernate-testing/src/main/java/org/hibernate/testing/boot/ServiceRegistryTestingImpl.java b/hibernate-testing/src/main/java/org/hibernate/testing/boot/ServiceRegistryTestingImpl.java
index 2bdc43fe25..7808d46a65 100644
--- a/hibernate-testing/src/main/java/org/hibernate/testing/boot/ServiceRegistryTestingImpl.java
+++ b/hibernate-testing/src/main/java/org/hibernate/testing/boot/ServiceRegistryTestingImpl.java
@@ -33,8 +33,15 @@ public class ServiceRegistryTestingImpl
 		extends StandardServiceRegistryImpl
 		implements ServiceRegistryImplementor {
 
+	private ServiceRegistryTestingImpl(
+			boolean autoCloseRegistry,
+			BootstrapServiceRegistry bootstrapServiceRegistry,
+			Map<String, Object> configurationValues) {
+		super( autoCloseRegistry, bootstrapServiceRegistry, configurationValues );
+	}
+
 	public static ServiceRegistryTestingImpl forUnitTesting() {
-		return new ServiceRegistryTestingImpl(
+		return ServiceRegistryTestingImpl.create(
 				true,
 				new BootstrapServiceRegistryBuilder().build(),
 				StandardServiceInitiators.LIST,
@@ -47,7 +54,7 @@ public class ServiceRegistryTestingImpl
 	}
 
 	public static ServiceRegistryTestingImpl forUnitTesting(Map<String,Object> settings) {
-		return new ServiceRegistryTestingImpl(
+		return ServiceRegistryTestingImpl.create(
 				true,
 				new BootstrapServiceRegistryBuilder().build(),
 				StandardServiceInitiators.LIST,
@@ -70,12 +77,17 @@ public class ServiceRegistryTestingImpl
 		);
 	}
 
-	public ServiceRegistryTestingImpl(
+	public static ServiceRegistryTestingImpl create(
 			boolean autoCloseRegistry,
 			BootstrapServiceRegistry bootstrapServiceRegistry,
 			List<StandardServiceInitiator<?>> serviceInitiators,
 			List<ProvidedService<?>> providedServices,
 			Map<String,Object> configurationValues) {
-		super( autoCloseRegistry, bootstrapServiceRegistry, serviceInitiators, providedServices, configurationValues );
+
+		ServiceRegistryTestingImpl instance = new ServiceRegistryTestingImpl( autoCloseRegistry, bootstrapServiceRegistry, configurationValues );
+		instance.initialize();
+		instance.applyServiceRegistrations( serviceInitiators, providedServices );
+
+		return instance;
 	}
 }
diff --git a/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/validation/MockSessionFactory.java b/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/validation/MockSessionFactory.java
index 206af4f01f..2f2aa00fce 100644
--- a/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/validation/MockSessionFactory.java
+++ b/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/validation/MockSessionFactory.java
@@ -150,7 +150,7 @@ public abstract class MockSessionFactory
 
 	public MockSessionFactory() {
 
-		serviceRegistry = new StandardServiceRegistryImpl(
+		serviceRegistry = StandardServiceRegistryImpl.create(
 				new BootstrapServiceRegistryBuilder().applyClassLoaderService(new ClassLoaderServiceImpl() {
 					@Override
 					@SuppressWarnings("unchecked")