Add support for BeanRegistrar registration on GenericApplicationContext

Closes gh-34574

spring-beans/src/main/java/org/springframework/beans/factory/BeanRegistrar.java

@@ -60,9 +60,10 @@ import org.springframework.core.env.Environment;
 public interface BeanRegistrar {
 
 	/**
-	 * Register beans in a programmatic way.
-	 * @param registry the bean registry
+	 * Register beans on the given {@link BeanRegistry} in a programmatic way.
+	 * @param registry the bean registry to operate on
 	 * @param env the environment that can be used to get the active profile or some properties
 	 */
 	void register(BeanRegistry registry, Environment env);
+
 }

spring-beans/src/main/java/org/springframework/beans/factory/support/BeanRegistryAdapter.java

@@ -56,6 +56,12 @@ public class BeanRegistryAdapter implements BeanRegistry {
 	private final @Nullable MultiValueMap<String, BeanDefinitionCustomizer> customizers;
 
 
+	public BeanRegistryAdapter(DefaultListableBeanFactory beanFactory, Environment environment,
+			Class<? extends BeanRegistrar> beanRegistrarClass) {
+
+		this(beanFactory, beanFactory, environment, beanRegistrarClass, null);
+	}
+
 	public BeanRegistryAdapter(BeanDefinitionRegistry beanRegistry, ListableBeanFactory beanFactory,
 			Environment environment, Class<? extends BeanRegistrar> beanRegistrarClass) {
 
@@ -73,6 +79,7 @@ public class BeanRegistryAdapter implements BeanRegistry {
 		this.customizers = customizers;
 	}
 
+
 	@Override
 	public <T> String registerBean(Class<T> beanClass) {
 		String beanName = BeanDefinitionReaderUtils.uniqueBeanName(beanClass.getName(), this.beanRegistry);
@@ -154,7 +161,8 @@ public class BeanRegistryAdapter implements BeanRegistry {
 		}
 	}
 
-	static class BeanSpecAdapter<T> implements Spec<T> {
+
+	private static class BeanSpecAdapter<T> implements Spec<T> {
 
 		private final RootBeanDefinition beanDefinition;
 
@@ -239,7 +247,8 @@ public class BeanRegistryAdapter implements BeanRegistry {
 		}
 	}
 
-	static class SupplierContextAdapter implements SupplierContext {
+
+	private static class SupplierContextAdapter implements SupplierContext {
 
 		private final ListableBeanFactory beanFactory;