Protect against non-deterministic method order in JDK7

- Allow reset of GlobalAdvisorAdapterRegistry

   Provide a reset() method allowing the GlobalAdvisorAdapterRegistry
   instance to be replaced with a fresh instance. This method has
   primarily been added to allow unit tests to leave the registry
   in a known state.

 - Protect against the fact that calls to configuration class methods
   my occur in a random order.

Issue: SPR-9779

spring-aop/src/main/java/org/springframework/aop/framework/adapter/GlobalAdvisorAdapterRegistry.java

@@ -1,12 +1,12 @@
 /*
- * Copyright 2002-2005 the original author or authors.
- * 
+ * Copyright 2002-2012 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.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -21,6 +21,7 @@ package org.springframework.aop.framework.adapter;
  *
  * @author Rod Johnson
  * @author Juergen Hoeller
+ * @author Phillip Webb
  * @see DefaultAdvisorAdapterRegistry
  */
 public abstract class GlobalAdvisorAdapterRegistry {
@@ -28,13 +29,22 @@ public abstract class GlobalAdvisorAdapterRegistry {
 	/**
 	 * Keep track of a single instance so we can return it to classes that request it.
 	 */
-	private static final AdvisorAdapterRegistry instance = new DefaultAdvisorAdapterRegistry();
-	
+	private static AdvisorAdapterRegistry instance = new DefaultAdvisorAdapterRegistry();
+
 	/**
-	 * Return the singleton DefaultAdvisorAdapterRegistry instance.
+	 * Return the singleton {@link DefaultAdvisorAdapterRegistry} instance.
 	 */
 	public static AdvisorAdapterRegistry getInstance() {
 		return instance;
 	}
 
+	/**
+	 * Reset the singleton {@link DefaultAdvisorAdapterRegistry}, removing any
+	 * {@link AdvisorAdapterRegistry#registerAdvisorAdapter(AdvisorAdapter) registered}
+	 * adapters.
+	 */
+	static void reset() {
+		instance = new DefaultAdvisorAdapterRegistry();
+	}
+
 }