Confused about bean's lifecycle method chain

[Sain Euwhyn]

public class Life implements BeanNameAware, BeanFactoryAware,
		ApplicationContextAware, BeanPostProcessor, InitializingBean,
		DisposableBean {
	private int counter; // counter

	public int getCounter() {
		return counter;
	}

	public void setCounter(int counter) {
		this.counter = counter;
		System.out.println("1. Spring setter DI：" + this.counter);
	}

	public Life() {
		System.out.println("0. Spring calls constructor");
	}

	@Override
	public void destroy() throws Exception {
		System.out.println("8. DisposableBean#destroy：" + ++counter);
	}

	public void _destroy() throws Exception {
		System.out.println("8'. bean#_destroy：" + ++counter);
	}

	@Override
	public void afterPropertiesSet() throws Exception {
		System.out.println(new Date().getTime());
		System.out.println("6. InitializingBean#afterPropertiesSet："
				+ ++counter);
	}

	public void init() throws Exception {
		System.out.println("6'. bean#init：" + ++counter);
	}

	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName)
			throws BeansException {
		System.out.println(new Date().getTime());
		System.out
				.println("5. BeanPostProcessor#postProcessBeforeInitialization："
						+ ++counter);
		return bean;
	}

	@Override
	public Object postProcessAfterInitialization(Object bean, String beanName)
			throws BeansException {
		System.out
				.println("7. BeanPostProcessor#postProcessAfterInitialization："
						+ ++counter);
		return bean;
	}

	@Override
	public void setApplicationContext(ApplicationContext applicationContext)
			throws BeansException {
		System.out.println("4. ApplicationContextAware#setApplicationContext："
				+ ++counter);
	}

	@Override
	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
		System.out.println("3. BeanFactoryAware#setBeanFactory：" + ++counter);
	}

	@Override
	public void setBeanName(String name) {
		System.out.println("2. BeanNameAware#setBeanName：" + ++counter);
	}
}

public class Test {
	public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext(
				"life.xml");
		context.getBean("holder");
	}
}

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> <bean id="life" class="test.Life" init-method="init" destroy-method="_destroy"> <property name="counter" value="1" /> </bean> <bean id="holder" class="java.lang.String" /> </beans>
-----------------------------------------------------------------------------------------
why the output is:

0. Spring calls constructor
1. Spring setter DI：1
2. BeanNameAware#setBeanName：2
3. BeanFactoryAware#setBeanFactory：3
4. ApplicationContextAware#setApplicationContext：4
1320491454906
6. InitializingBean#afterPropertiesSet：5
6'. bean#init：6
1320491454921
5. BeanPostProcessor#postProcessBeforeInitialization：7
7. BeanPostProcessor#postProcessAfterInitialization：8

According to <<Spring in Action 3rd>> and Spring-Reference:

6 If any of the beans implement the BeanPostProcessor interface, Spring calls
their postProcessBeforeInitialization() method.
7 If any beans implement the InitializingBean interface, Spring calls their
afterPropertiesSet() method. Similarly, if the bean was declared with an
init-method, then the specified initialization method will be called.

It seems that there is something wrong with the order?!

[Saifuddin Merchant]

BeanPostProcessor are special beans that are created before any other (regular) beans are created.

postProcessBeforeInitialization will not be applied on the BeanPostProcessor itself but is called once for every other bean that is created.

In you example configuration if you remove the other bean
<bean id="holder" class="java.lang.String" />you will find that the sysout will not contain

5. BeanPostProcessor#postProcessBeforeInitialization：7
7. BeanPostProcessor#postProcessAfterInitialization：8


Similarly if you add multiple beans you will see the post processor being called once for each Bean!


The rule,

If any of the beans implement the BeanPostProcessor interface, Spring calls
their postProcessBeforeInitialization() method.
7 If any beans implement the InitializingBean interface, Spring calls their
afterPropertiesSet() method. Similarly, if the bean was declared with an
init-method, then the specified initialization method will be called.

applies for regular beans not for bean that themselves implement the BeanPostProcessor interface.

[Vijitha Kumara]

And welcome to the CodeRanch, Sain Euwhyn!

[Sain Euwhyn]

Thanks so much Sam Mercs!~
I'm new to Spring, you just helped me about my problem which puzzled me days, and I couldn't find proper answer from <<Spring in Action>>.
By the way, thanks Vijitha also, you are very hospitable! And I'm appologize for the late reply~~