@PostConstruct and @PreDestroy in Spring Boot - Mini Project: Build & Apply

Using @PostConstruct and @PreDestroy in Spring Boot

📖 Scenario: You are building a simple Spring Boot service that needs to perform setup right after the service starts and cleanup just before it stops.This is like preparing your kitchen before cooking and cleaning it after you finish.

🎯 Goal: Create a Spring Boot component that uses @PostConstruct to run initialization code after the bean is created, and @PreDestroy to run cleanup code before the bean is destroyed.

📋 What You'll Learn

Create a Spring component class named KitchenService

Add a method annotated with @PostConstruct that prints "Kitchen is ready"

Add a method annotated with @PreDestroy that prints "Kitchen is cleaned"

Use the System.out.println statements exactly as specified

💡 Why This Matters

🌍 Real World

Many applications need to initialize resources like database connections or caches after startup and release them before shutdown to avoid resource leaks.

💼 Career

Understanding bean lifecycle annotations like @PostConstruct and @PreDestroy is essential for writing robust Spring Boot applications that manage resources properly.

1

Create the KitchenService class

Create a public class named KitchenService annotated with @Component.

Spring Boot

@Component
public class KitchenService {
    // Your code here
}

Need a hint?

Use @Component to make the class a Spring bean.

2

Add @PostConstruct method

Inside KitchenService, add a public method named init annotated with @PostConstruct that calls System.out.println("Kitchen is ready").

Spring Boot

import jakarta.annotation.PostConstruct;

@Component
public class KitchenService {
    // Your code here
}

Need a hint?

Use @PostConstruct to mark the method that runs after bean creation.

3

Add @PreDestroy method

Inside KitchenService, add a public method named cleanup annotated with @PreDestroy that calls System.out.println("Kitchen is cleaned").

Spring Boot

import jakarta.annotation.PreDestroy;

@Component
public class KitchenService {
    @PostConstruct
    public void init() {
        System.out.println("Kitchen is ready");
    }
    // Your code here
}

Need a hint?

Use @PreDestroy to mark the method that runs before bean destruction.

4

Complete the Spring Boot application

Create a SpringBootApplication class named KitchenApp with a main method that runs the application using SpringApplication.run(KitchenApp.class, args).

Spring Boot

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class KitchenApp {
    // Your code here
}

Need a hint?

This class starts the Spring Boot application.