Refine null-safety in more modules

This commit refines the null-safety in:
 - spring-jdbc
 - spring-r2dbc
 - spring-orm
 - spring-beans
 - spring-aop

See gh-32475

spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/AspectJAdvisorBeanRegistrationAotProcessor.java

@@ -22,6 +22,7 @@ import org.springframework.beans.factory.aot.BeanRegistrationAotContribution;
 import org.springframework.beans.factory.aot.BeanRegistrationAotProcessor;
 import org.springframework.beans.factory.aot.BeanRegistrationCode;
 import org.springframework.beans.factory.support.RegisteredBean;
+import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 
 /**
@@ -38,6 +39,7 @@ class AspectJAdvisorBeanRegistrationAotProcessor implements BeanRegistrationAotP
 
 
 	@Override
+	@Nullable
 	public BeanRegistrationAotContribution processAheadOfTime(RegisteredBean registeredBean) {
 		if (aspectjPresent) {
 			Class<?> beanClass = registeredBean.getBeanClass();

spring-aop/src/main/java/org/springframework/aop/config/SpringConfiguredBeanDefinitionParser.java

@@ -23,6 +23,7 @@ import org.springframework.beans.factory.parsing.BeanComponentDefinition;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link BeanDefinitionParser} responsible for parsing the
@@ -51,6 +52,7 @@ class SpringConfiguredBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		if (!parserContext.getRegistry().containsBeanDefinition(BEAN_CONFIGURER_ASPECT_BEAN_NAME)) {
 			RootBeanDefinition def = new RootBeanDefinition();

spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java

@@ -270,6 +270,7 @@ public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport
 	}
 
 	@Override
+	@Nullable
 	public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) {
 		Object cacheKey = getCacheKey(beanClass, beanName);
 
@@ -311,6 +312,7 @@ public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport
 	 * @see #getAdvicesAndAdvisorsForBean
 	 */
 	@Override
+	@Nullable
 	public Object postProcessAfterInitialization(@Nullable Object bean, String beanName) {
 		if (bean != null) {
 			Object cacheKey = getCacheKey(bean.getClass(), beanName);

spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/BeanNameAutoProxyCreator.java

@@ -81,6 +81,7 @@ public class BeanNameAutoProxyCreator extends AbstractAutoProxyCreator {
 	 * @see #setBeanNames(String...)
 	 */
 	@Override
+	@Nullable
 	protected TargetSource getCustomTargetSource(Class<?> beanClass, String beanName) {
 		return (isSupportedBeanName(beanClass, beanName) ?
 				super.getCustomTargetSource(beanClass, beanName) : null);

spring-aop/src/main/java/org/springframework/aop/scope/ScopedProxyBeanRegistrationAotProcessor.java

@@ -53,6 +53,7 @@ class ScopedProxyBeanRegistrationAotProcessor implements BeanRegistrationAotProc
 
 
 	@Override
+	@Nullable
 	public BeanRegistrationAotContribution processAheadOfTime(RegisteredBean registeredBean) {
 		Class<?> beanClass = registeredBean.getBeanClass();
 		if (beanClass.equals(ScopedProxyFactoryBean.class)) {

spring-aop/src/main/java/org/springframework/aop/scope/ScopedProxyFactoryBean.java

@@ -117,6 +117,7 @@ public class ScopedProxyFactoryBean extends ProxyConfig
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		if (this.proxy == null) {
 			throw new FactoryBeanNotInitializedException();
@@ -125,6 +126,7 @@ public class ScopedProxyFactoryBean extends ProxyConfig
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getObjectType() {
 		if (this.proxy != null) {
 			return this.proxy.getClass();