AspectJWeavingEnabler registered with well-defined bean name (and therefore once only)

Issue: SPR-14373

spring-context/src/main/java/org/springframework/context/config/LoadTimeWeaverBeanDefinitionParser.java

 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.context.config;
 import org.w3c.dom.Element;
 
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.parsing.BeanComponentDefinition;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.RootBeanDefinition;
@@ -36,15 +37,22 @@ import org.springframework.util.ClassUtils;
  */
 class LoadTimeWeaverBeanDefinitionParser extends AbstractSingleBeanDefinitionParser {
 
-	private static final String WEAVER_CLASS_ATTRIBUTE = "weaver-class";
+	/**
+	 * The bean name of the internally managed AspectJ weaving enabler.
+	 * @since 4.3.1
+	 */
+	public static final String ASPECTJ_WEAVING_ENABLER_BEAN_NAME =
+			"org.springframework.context.config.internalAspectJWeavingEnabler";
 
-	private static final String ASPECTJ_WEAVING_ATTRIBUTE = "aspectj-weaving";
+	private static final String ASPECTJ_WEAVING_ENABLER_CLASS_NAME =
+			"org.springframework.context.weaving.AspectJWeavingEnabler";
 
 	private static final String DEFAULT_LOAD_TIME_WEAVER_CLASS_NAME =
 			"org.springframework.context.weaving.DefaultContextLoadTimeWeaver";
 
-	private static final String ASPECTJ_WEAVING_ENABLER_CLASS_NAME =
-			"org.springframework.context.weaving.AspectJWeavingEnabler";
+	private static final String WEAVER_CLASS_ATTRIBUTE = "weaver-class";
+
+	private static final String ASPECTJ_WEAVING_ATTRIBUTE = "aspectj-weaving";
 
 
 	@Override
@@ -65,9 +73,11 @@ class LoadTimeWeaverBeanDefinitionParser extends AbstractSingleBeanDefinitionPar
 		builder.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
 
 		if (isAspectJWeavingEnabled(element.getAttribute(ASPECTJ_WEAVING_ATTRIBUTE), parserContext)) {
-			RootBeanDefinition weavingEnablerDef = new RootBeanDefinition();
-			weavingEnablerDef.setBeanClassName(ASPECTJ_WEAVING_ENABLER_CLASS_NAME);
-			parserContext.getReaderContext().registerWithGeneratedName(weavingEnablerDef);
+			if (!parserContext.getRegistry().containsBeanDefinition(ASPECTJ_WEAVING_ENABLER_BEAN_NAME)) {
+				RootBeanDefinition def = new RootBeanDefinition(ASPECTJ_WEAVING_ENABLER_CLASS_NAME);
+				parserContext.registerBeanComponent(
+						new BeanComponentDefinition(def, ASPECTJ_WEAVING_ENABLER_BEAN_NAME));
+			}
 
 			if (isBeanConfigurerAspectEnabled(parserContext.getReaderContext().getBeanClassLoader())) {
 				new SpringConfiguredBeanDefinitionParser().parse(element, parserContext);