@PostConstruct and @PreDestroy in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to mark a method that runs after the bean is created.

Spring Boot

public class MyService {
    [1]
    public void init() {
        System.out.println("Bean initialized");
    }
}

Drag options to blanks, or click blank then click option'

A@Service

B@PreDestroy

C@Autowired

D@PostConstruct

Attempts:

3 left

💡 Hint

Common Mistakes

Using @PreDestroy instead of @PostConstruct

Forgetting to import the annotation

Placing the annotation on the class instead of the method

The @PostConstruct annotation marks a method to be run after the bean is created and dependencies are injected.

2fill in blank

medium

Complete the code to mark a method that runs before the bean is destroyed.

Spring Boot

public class MyService {
    [1]
    public void cleanup() {
        System.out.println("Bean is being destroyed");
    }
}

Drag options to blanks, or click blank then click option'

A@PreDestroy

B@PostConstruct

C@Bean

D@Component

Attempts:

3 left

💡 Hint

Common Mistakes

Using @PostConstruct instead of @PreDestroy

Not having a method with void return type

Placing the annotation on a static method

The @PreDestroy annotation marks a method to be run just before the bean is destroyed, useful for cleanup.

3fill in blank

hard

Fix the error in the code by choosing the correct annotation for the method that runs after bean creation.

Spring Boot

public class ResourceLoader {
    public void load() {
        System.out.println("Loading resources");
    }

    [1]
    public void init() {
        load();
    }
}

Drag options to blanks, or click blank then click option'

A@Autowired

B@PreDestroy

C@PostConstruct

D@Service

Attempts:

3 left

💡 Hint

Common Mistakes

Using @PreDestroy which runs before bean destruction

Missing the annotation causing the method not to run automatically

The init() method should be annotated with @PostConstruct to run after the bean is created.

4fill in blank

hard

Fill both blanks to correctly annotate methods for initialization and cleanup in a Spring bean.

Spring Boot

public class ConnectionManager {
    [1]
    public void start() {
        System.out.println("Connection started");
    }

    [2]
    public void stop() {
        System.out.println("Connection stopped");
    }
}

Drag options to blanks, or click blank then click option'

A@PostConstruct

B@Autowired

C@PreDestroy

D@Component

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the annotations between methods

Using @Autowired instead of lifecycle annotations

The start() method uses @PostConstruct to run after bean creation, and stop() uses @PreDestroy to run before destruction.

5fill in blank

hard

Fill all three blanks to create a Spring bean with proper lifecycle methods for initialization and destruction.

Spring Boot

import jakarta.annotation.[1];
import jakarta.annotation.[2];

public class CacheService {

    [3]
    public void setup() {
        System.out.println("Cache setup complete");
    }

    @PreDestroy
    public void clear() {
        System.out.println("Cache cleared");
    }
}

Drag options to blanks, or click blank then click option'

APostConstruct

BPreDestroy

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Importing wrong packages

Forgetting to annotate setup() with @PostConstruct

Using @Component as an annotation for methods

The imports must include PostConstruct and PreDestroy. The setup() method is annotated with @PostConstruct to run after bean creation.