CODEWITHSUNDEEP
javaspring
Anand
Anand

Reputation: 21358

Getting BeanNotOfRequiredTypeException in Spring while using BeanPostProcessor

I am trying to run a Spring example using BeanPostProcessor.

Below is the bean post processor

public class DisplayNamePostProcessor implements BeanPostProcessor{

    DisplayNamePostProcessor(){
        System.out.println("DisplayNamePostProcessor instantiated");
    }

    public Object postProcessBeforeInitialization(Object bean, String beanName)
            throws BeansException {
        System.out.println("postProcessBeforeInitialization for bean "+beanName);

        return this;
    }

    public Object postProcessAfterInitialization(Object bean, String beanName)
            throws BeansException {
        System.out.println("postProcessAfterInitialization for bean "+beanName);
        return this;
    }

}

here, is the spring configuration file

    <bean id="car" class="com.core.Car" >
            <property name="wheel" value="four" />
        </bean>
<bean class="com.core.DisplayNamePostProcessor"></bean>

Here, is my bean class

public class Car {

    private String wheel; 

    public String getWheel() {
        return wheel;
    } 
    public void setWheel(String wheel) {
        this.wheel = wheel;
    } 


    public static void main(String[] args) {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        System.out.println("application context loaded");
        Car car = context.getBean("car", Car.class);
    }
}

On running the above main method, I am getting the below exception

Exception in thread "main" org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'car' must be of type [com.core.Car], but was actually of type [com.core.DisplayNamePostProcessor]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:361)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:198)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1121)

Can someone please let me know what Ia m doing wrong and how to resolve this exception. Also, what is the root cause of it?

Upvotes: 0

Views: 300

Answers (1)

Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 280179

Any BeanPostProcessor beans you declare will be picked up by the ApplicationContext bean factory and used. Your implementation does this

public Object postProcessBeforeInitialization(Object bean, String beanName)
        throws BeansException {
    System.out.println("postProcessBeforeInitialization for bean "+beanName);

    return this;
}

Instead of doing anything to the target bean, it simply returns itself. It thus overrides all beans it processes with a DisplayNamePostProcessor bean.

Upvotes: 1

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