Spring Frequently Asked Questions
These questions are the most important for interview and written by industry expert.Explain Bean lifecycle in Spring framework?
- The spring container finds the bean’s definition from the XML file and instantiates the bean.
- Using the dependency injection, spring populates all of the properties as specified in the bean definition.
- If the bean implements the BeanNameAware interface, the factory calls setBeanName() passing the bean’s ID.
- If the bean implements the BeanFactoryAware interface, the factory calls setBeanFactory(), passing an instance of itself.
- If there are any BeanPostProcessors associated with the bean, their post- ProcessBeforeInitialization() methods will be called.
- If an init-method is specified for the bean, it will be called.
- Finally, if there are any BeanPostProcessors associated with the bean, their postProcessAfterInitialization() methods will be called.
What is Spring ?
Spring is a lightweight inversion of control(IoC) and aspect-oriented container framework.
What is XMLBeanFactory?
BeanFactory has many implementations in Spring. But one of the most useful one is
To retrieve the bean from a BeanFactory, call the getBean() method by passing the name of the bean you want to retrieve.
org.springframework.beans.factory.xml.XmlBeanFactory
, which loads its beans based on the definitions contained in an XML file. To create an XmlBeanFactory
, pass a java.io.InputStream
to the constructor. The InputStream
will provide the XML to the factory. For example, the following code snippet uses a java.io.FileInputStream
to provide a bean definition XML file to XmlBeanFactory
. BeanFactory factory = new XmlBeanFactory(new FileInputStream("beans.xml"));
To retrieve the bean from a BeanFactory, call the getBean() method by passing the name of the bean you want to retrieve.
MyBean myBean = (MyBean) factory.getBean("myBean")