Spring Batch - “job” scoped beans can not be injec

Question

I am using spring batch version 3.0.2.RELEASE and spring framework version 3.2.12.RELEASE. And I am trying to inject a job scoped bean to another job scoped bean.

My configuration looks like this

<bean id="beanA" class="com.trial.BeanA" scope="job" >
    <property name="beanB" ref="beanB" />
</bean>

<bean id="beanB" class="com.trial.BeanB" scope="job"/>

It throws an exception with details:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.beanA' defined in class path resource [trial-context.xml]: Initialization of bean failed; nested exception is org.springframework.beans.ConversionNotSupportedException: Failed to convert property value of type 'com.sun.proxy.$Proxy1 implementing com.trial.BeanB,org.springframework.beans.factory.InitializingBean,org.springframework.aop.scope.ScopedObject,java.io.Serializable,org.springframework.aop.framework.AopInfrastructureBean,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised' to required type 'com.trial.BeanB' for property 'beanB'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [com.sun.proxy.$Proxy1 implementing com.trial.BeanB,org.springframework.beans.factory.InitializingBean,org.springframework.aop.scope.ScopedObject,java.io.Serializable,org.springframework.aop.framework.AopInfrastructureBean,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised] to required type [com.trial.BeanB] for property 'beanB': no matching editors or conversion strategy found
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:529)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$2.getObject(AbstractBeanFactory.java:331)
    at org.springframework.batch.core.scope.JobScope.get(JobScope.java:103)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:327)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:191)
    at org.springframework.aop.target.SimpleBeanTargetSource.getTarget(SimpleBeanTargetSource.java:34)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:184)
    at com.sun.proxy.$Proxy13.getValue(Unknown Source)
    at org.springframework.batch.core.listener.CompositeJobExecutionListener.beforeJob(CompositeJobExecutionListener.java:73)
    at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:301)
    at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:135)
    at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:49)
    at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:128)
Caused by: org.springframework.beans.ConversionNotSupportedException: Failed to convert property value of type 'com.sun.proxy.$Proxy1 implementing com.trial.BeanB,org.springframework.beans.factory.InitializingBean,org.springframework.aop.scope.ScopedObject,java.io.Serializable,org.springframework.aop.framework.AopInfrastructureBean,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised' to required type 'com.trial.BeanB' for property 'beanB'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [com.sun.proxy.$Proxy1 implementing com.trial.BeanB,org.springframework.beans.factory.InitializingBean,org.springframework.aop.scope.ScopedObject,java.io.Serializable,org.springframework.aop.framework.AopInfrastructureBean,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised] to required type [com.trial.BeanB] for property 'beanB': no matching editors or conversion strategy found
    at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:464)
    at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:495)
    at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:489)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.convertForProperty(AbstractAutowireCapableBeanFactory.java:1465)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1424)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1160)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    ... 18 more
Caused by: java.lang.IllegalStateException: Cannot convert value of type [com.sun.proxy.$Proxy1 implementing com.trial.BeanB,org.springframework.beans.factory.InitializingBean,org.springframework.aop.scope.ScopedObject,java.io.Serializable,org.springframework.aop.framework.AopInfrastructureBean,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised] to required type [com.trial.BeanB] for property 'beanB': no matching editors or conversion strategy found
    at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:267)
    at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:449)
    ... 24 more

Even I try to inject a "job" scoped bean to a "step" scoped bean, it fails and throws a similar exception.

How can I solve the issue?

Answer 1

You are using java proxying which requires interfaces, yet your BeanB doesn't implement an interface that BeanA is coded against. You need to either switch to dynamic subclassing or have BeanB implement an interface and have BeanA expect that interface.