I tried creating a simple AOP example in Spring. But, I get AOP errors.
Knight.java
package com.springinaction.knights;
public abstract class Knight {
public abstract void embarkQuest() ;
}
DragonSlayingKnights.java
package com.springinaction.knights;
public class DragonSlayingKnights extends Knight {
Quest quest;
public DragonSlayingKnights(Quest quest){
this.quest = quest ;
}
@Override
public void embarkQuest() {
quest.embark();
}
}
FightingKnight.java
package com.springinaction.knights;
public class FightingKnight extends Knight {
Quest quest ;
public FightingKnight(Quest quest){
this.quest = quest;
}
@Override
public void embarkQuest() {
quest.embark();
}
}
Quest.java
package com.springinaction.knights;
public abstract class Quest {
public abstract void embark();
}
DragonSlayingQuest.java
package com.springinaction.knights;
public class DragonSlayingQuest extends Quest {
@Override
public void embark() {
System.out.println("I am on a Dragon Slaying Quest");
}
}
FightingQuest.java
package com.springinaction.knights;
public class FightingQuest extends Quest {
@Override
public void embark() {
System.out.println("I am on a Fighting Quest");
}
}
Minstrel.java
package com.springinaction.knights;
public class Minstrel {
public void singBeforeQuest(){
System.out.println("Falala;Theknightissobrave!");
}
public void singAfterQuest(){
System.out.println("Tee heehe;Thebraveknightdidembarkonaquest!");
}
}
configuration.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
<bean id="knight" class="com.springinaction.knights.DragonSlayingKnights">
<constructor-arg ref="quest"/>
</bean>
<bean id="quest" class="com.springinaction.knights.DragonSlayingQuest"/>
<bean id="minstrel" class="com.springinaction.knights.Minstrel"/>
<aop:config>
<aop:aspect ref="minstrel">
<aopointcut id="embark" expression="execution(*com.springinaction.knights.Knight.embarkQuest(..)) " />
<aop:before pointcut-ref="embark" method="singBeforeQuest"/>
<aop:after pointcut-ref="embark" method="singAfterQuest"/>
</aop:aspect>
</aop:config>
</beans>
Test File – TestKnights.java
package com.test.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlAp plicationContext;
import com.springinaction.knights.Knight;
public class TestKnights {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("configuration.xml" );
Knight knight = (Knight) context.getBean("knight");
knight.embarkQuest();
}
}
When I execute the TestKnights.java, I get the following error:
Nov 5, 2011 8:59:46 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5d764be1: startup date [Sat Nov 05 20:59:46 PDT 2011]; root of context hierarchy
Nov 5, 2011 8:59:46 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [configuration.xml]
Nov 5, 2011 8:59:46 PM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@485fcf29: defining beans [knight,quest,minstrel,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.aop.aspectj.AspectJPointcutAdvisor#0,org.springframework.aop.aspectj.AspectJPointcutAdvisor#1,embark]; root of factory hierarchy
Nov 5, 2011 8:59:46 PM org.springframework.beans.factory.support.DefaultSingletonBeanRegistry destroySingletons
INFO: Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@485fcf29: defining beans [knight,quest,minstrel,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.aop.aspectj.AspectJPointcutAdvisor#0,org.springframework.aop.aspectj.AspectJPointcutAdvisor#1,embark]; root of factory hierarchy
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'knight' defined in class path resource [configuration.xml]: BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.aop.aspectj.AspectJPointcutAdvisor#0': Cannot create inner bean '(inner bean)' of type [org.springframework.aop.aspectj.AspectJMethodBeforeAdvice] while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)': Cannot resolve reference to bean 'embark' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:452)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:293)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:290)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:192)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:585)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425)
at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:83)
at com.test.spring.TestKnights.main(TestKnights.java:9)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.aop.aspectj.AspectJPointcutAdvisor#0': Cannot create inner bean '(inner bean)' of type [org.springframework.aop.aspectj.AspectJMethodBeforeAdvice] while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)': Cannot resolve reference to bean 'embark' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:281)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:125)
at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:630)
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:148)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1003)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:907)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:293)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:290)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196)
at org.springframework.aop.framework.autoproxy.BeanFactoryAdvisorRetrievalHelper.findAdvisorBeans(BeanFactoryAdvisorRetrievalHelper.java:86)
at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.findCandidateAdvisors(AbstractAdvisorAutoProxyCreator.java:100)
at org.springframework.aop.aspectj.autoproxy.AspectJAwareAdvisorAutoProxyCreator.shouldSkip(AspectJAwareAdvisorAutoProxyCreator.java:107)
at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessBeforeInstantiation(AbstractAutoProxyCreator.java:278)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInstantiation(AbstractAutowireCapableBeanFactory.java:848)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeforeInstantiation(AbstractAutowireCapableBeanFactory.java:820)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:446)
… 10 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)': Cannot resolve reference to bean 'embark' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:106)
at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:616)
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:148)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1003)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:907)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:270)
… 28 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:965)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:911)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:312)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:192)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:322)
… 36 more
Caused by: java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389)
at java.lang.Class.getConstructor0(Class.java:2699)
at java.lang.Class.getDeclaredConstructor(Class.java:1985)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:65)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:958)
… 42 more
Caused by: java.lang.ClassNotFoundException: org.aspectj.weaver.reflect.ReflectionWorld$ReflectionWorldException
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
… 48 more
Best Answer
You need AspectJ on the classpath. It does not come with Spring.