Explain lifecycle of a bean in Spring framework.

When a bean is instantiated, it may be required to perform some initialization to get it into a usable state. Similarly, when the bean is no longer required and is removed from the container, some cleanup may be required.

Spring bean factory is responsible for managing the life cycle of a Spring bean created through spring container. The life cycle of a bean consist of call back methods that can be broadly categorized into 2 groups:

• Post initialization call back methods.
• Pre destruction call back methods.

Spring framework also provides the following 4 ways to control the life cycle events of a bean:

• InitializingBean and DisposableBean callback interfaces.
• Other Aware interfaces for specific behavior.
• Custom init() and destroy() methods in bean configuration file.
• @PostConstruct and @PreDestroy annotations.

For example, Below configured beanCustomInit() and beanCustomDestroy() methods of the bean are the examples of life cycle method of Employee Bean.

<beans>
    <bean id="empBean" class="net.javapedia.spring.EmployeeBean"
            init-method="beanCustomInit" destroy-method="beanCustomDestroy"></bean>
</beans>