Interview Questions: Spring IoC Container
June 11, 2013
|Qns-1: Which packages is the basis of Spring IoC container?|
|Ans: a. org.springframework.beans b. org.springframework.context|
|Qns-2: What is the role of BeanFactory in Spring IoC container?|
|Ans: BeanFactory provides the configuration mechanism so that any type of object can be managed easily.|
|Qns-3: What is the role of ApplicationContext in Spring IoC container?|
|Ans: ApplicationContext extends BeanFactory. ApplicationContext helps to integrate other module like Spring AOP, messages resource , event publication, application-layer specific contexts.|
|Qns-4: How can we instantiate ApplicationContext in standalone application?|
|Ans: We need to call ClassPathXmlApplicationContext or FileSystemXmlApplicationContext.|
|Qns-5: What are the variants of dependency Injection?|
Ans: There are two variants of Dependency Injection.
a. Constructor-based dependency injection
b. Setter-based dependency injection
|Qns-6: What are disadvantages of autowiring in Spring?|
Ans: a. We cannot autowire primitives dat type, String and Classes.
b. Autowiring is not so exact as explicit wiring.
c. Autowiring will not be available for those tools that will generate documentation.
|Qns-7: How many beans scopes are there in Spring IoC Container?|
Ans: There are five Bean scopes.
e. Global Session
|Qns-8: How to customize the nature of a bean?|
a. Lifecycle callbacks can be customized by implementing interface InitializingBean and DisposableBean.
b. Startup and shutdown callbacks can be customized by implementing interface Lifecycle.
c. Use ApplicationContextAware and BeanNameAware.
|Qns-9: What is the role of BeanPostProcessor Interface?|
|Ans: Implementing BeanPostProcessor interface, we can write our own bean instantiation logic.|
|Qns-10: What is the role of PropertyPlaceholderConfigurer in spring?|
|Ans: PropertyPlaceholderConfigurer externalize property values from a bean definition to another separate file.|