Bean lifecycle overview in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Spring Bean?

A Spring Bean is an object that is managed by the Spring IoC container. It is created, configured, and managed by Spring during the application runtime.

beginner

Name the main phases of the Spring Bean lifecycle.

The main phases are: Instantiation, Property Population (Dependency Injection), Initialization, Usage, and Destruction.

intermediate

What happens during the Initialization phase of a Spring Bean?

During Initialization, Spring calls any custom initialization methods or lifecycle callbacks like @PostConstruct or afterPropertiesSet() to prepare the bean for use.

intermediate

How can you customize the destruction of a Spring Bean?

You can customize destruction by implementing DisposableBean interface, using @PreDestroy annotation, or specifying a destroy-method in the bean configuration.

beginner

What role does the Spring IoC container play in the Bean lifecycle?

The Spring IoC container controls the entire lifecycle of beans: creating, wiring dependencies, initializing, and destroying them when no longer needed.

Which annotation is used to run code after a Spring Bean has been initialized?

A @PostConstruct

B @PreDestroy

C @Autowired

D @Bean

@PostConstruct runs after the bean is fully initialized.

What is the first step in the Spring Bean lifecycle?

A Initialization

B Destruction

C Instantiation

D Dependency Injection

Instantiation is when the bean object is created.

Which interface can a Spring Bean implement to customize its destruction logic?

A InitializingBean

B DisposableBean

C BeanFactory

D ApplicationContext

DisposableBean interface allows custom destruction code.

When does Spring perform dependency injection on a bean?

A During property population phase

B After destruction

C Before instantiation

D After usage

Dependency injection happens during property population.

Which annotation marks a method to be called before a bean is destroyed?

A @PostConstruct

B @Component

C @Autowired

D @PreDestroy

@PreDestroy marks methods to run before bean destruction.

Explain the full lifecycle of a Spring Bean from creation to destruction.

Think about how Spring manages the bean step by step.

How can you add custom behavior during the initialization and destruction phases of a Spring Bean?

Consider both annotations and interfaces.