[Springframework-developer] Proxying target classes

[Colin S. <col...@ex...>]

Rod,

Have you ever seen cglib's EnhancerEmitter blow up on trying to create a 
proxy? I generally only have to proxy interfaces, so have not proxied 
classes too much so far, however I just had a case where I needed to 
proxy a class directly, and got the following exception:

 method 'onMessage' due to throwable 
[org.springframework.beans.factory.BeanCrea
tionException: Error creating bean with name 'packaging-engine' defined 
in class
path resource [packaging-applicationContext.xml]: Initialization method 
of bean
failed; nested exception is:
        org.springframework.aop.framework.AopConfigException: Unexpected 
AOP exc
eption; nested exception is:
        java.lang.NullPointerException]
08:07:48,585 INFO  [JtaTransactionManager] Initiating transaction rollback
08:07:48,585 ERROR [LogInterceptor] RuntimeException:
org.springframework.beans.factory.BeanCreationException: Error creating 
bean wit
h name 'packaging-engine' defined in classpath resource 
[packaging-applicationCo
ntext.xml]: Initialization method of bean failed; nested exception is:
        org.springframework.aop.framework.AopConfigException: Unexpected 
AOP exc
eption; nested exception is:
        java.lang.NullPointerException
org.springframework.aop.framework.AopConfigException: Unexpected AOP 
exception;
nested exception is:
        java.lang.NullPointerException
java.lang.NullPointerException
        at 
net.sf.cglib.proxy.EnhancerEmitter$4.getMethods(EnhancerEmitter.java:
407)
        at net.sf.cglib.proxy.NoOpGenerator.generate(NoOpGenerator.java:69)
        at 
net.sf.cglib.proxy.EnhancerEmitter.emitMethods(EnhancerEmitter.java:4
31)
        at 
net.sf.cglib.proxy.EnhancerEmitter.<init>(EnhancerEmitter.java:172)

This is using BeanNameAutoProxyCreator, with proxyTargetClass set to 
true. I actually used another postprocessor just for this case, since 
normally I only care about interfaces, so there's nothing else in it:

  <bean id="packaging-txAutoProxyCreator2" 
class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
    <property name="proxyTargetClass"><value>true</value></property>
    <property name="interceptorNames">
      <list>
        <idref bean="hibInterceptor"/>
        <idref local="packaging-matchAllTxInterceptor"/>
      </list>
    </property>
    <property name="beanNames">
      <list>
           <idref local="packaging-engine"/>
      </list>
    </property>
  </bean>

The class in question (Engine) is a fairly simple class. It implements 
no interfaces.

Regards,
Colin