Initial work to ensure CGLIB classes are not eagerly loaded (CGLIB should only be required if Spring users wish to process @Configuration classes)

org.springframework.config.java/src/main/java/org/springframework/config/java/FactoryMethod.java

@@ -56,7 +56,7 @@ public @interface FactoryMethod {
 	 * Specifies what interceptor should be used when processing this {@link FactoryMethod}.
 	 * Defaults to {@link NoOpInterceptor} which does nothing.
 	 */
-	Class<? extends MethodInterceptor> interceptor() default NoOpInterceptor.class;
+	Class<? extends MethodInterceptor> interceptor();
 
 	/**
 	 * Optionally specifies any {@link Validator} types capable of validating the syntax of

org.springframework.config.java/src/main/java/org/springframework/config/java/support/AbstractConfigurationClassProcessor.java

@@ -1,5 +1,7 @@
 package org.springframework.config.java.support;
 
+import static org.springframework.util.StringUtils.*;
+
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.config.java.ConfigurationModel;
@@ -7,6 +9,8 @@ import org.springframework.config.java.internal.parsing.ConfigurationParser;
 
 public abstract class AbstractConfigurationClassProcessor {
 	
+	static String CGLIB_PACKAGE = "net.sf.cglib.proxy";
+
 	protected abstract BeanDefinitionRegistry getConfigurationBeanDefinitions(boolean includeAbstractBeanDefs);
 	
 	protected abstract ConfigurationParser createConfigurationParser();
@@ -19,13 +23,21 @@ public abstract class AbstractConfigurationClassProcessor {
 		if(configBeanDefs.getBeanDefinitionCount() == 0)
 			return configBeanDefs; // nothing to do - don't waste any more cycles
 		
+		// TODO: the location of this cglib check is temporary, pending removal of the
+		// @FactoryMethod meta-annotation indirection
+		if(Package.getPackage(CGLIB_PACKAGE) == null)
+			throw new RuntimeException("CGLIB is required to process @Configuration classes. " +
+					"Either add CGLIB v2.2.3 to the classpath or remove the following " +
+					"@Configuration bean definitions: ["
+					+ arrayToCommaDelimitedString(configBeanDefs.getBeanDefinitionNames()) + "]");
+		
 		ConfigurationModel configModel = createConfigurationModelFor(configBeanDefs);
 		
 		validateModel(configModel);
 		
 		return renderModelAsBeanDefinitions(configModel);
 	}
-
+	
 	private ConfigurationModel createConfigurationModelFor(BeanDefinitionRegistry configBeanDefinitions) {
 
 		ConfigurationParser parser = createConfigurationParser();