Spring InitializingBean and DisposableBean - Example

In Spring, the InitializingBean and DisposableBean interfaces can be used to interact with the spring container’s management lifecycle. The container calls the afterPropertiesSet() method from the InitializingBean and the destroy() method from the DisposableBean respectively to perform certain actions upon bean initialization and destruction.

Annotations @PostConstruct and @PreDestroy, standardized by JSR-250, are generally considered the best practice for obtaining lifecycle callbacks in a modern Spring application. Utilizing these annotations designates that our beans are not bound to Spring-concrete interfaces. Using @PostConstruct and @PreDestroy in Spring - click here

If you don't optate to utilize JSR-250, consider the bean definition metadata init-method and destroy-method.

Complete Example 

We are creating a simple maven project. You could clone the code from our GitHub repo.

Final Project Directory

Complete pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
         http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.knf.dev.demo</groupId>
    <artifactId>spring-initializingbean-disposablebean-example</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>6.1.0</version>
        </dependency>
    </dependencies>
</project>

Create Component class

Create MyComponent class which implements InitializingBean and DisposableBean interfaces. Implement method afterPropertiesSet(), destroy() and have one printMessage() method. 

Here we are using Annotation-based configuration.

package com.knf.dev.demo;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Component;

@Component
public class MyComponent implements InitializingBean, DisposableBean {


    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("Perform initialization task.");
    }

    @Override
    public void destroy() {
        System.out.println("Perform destructive task or release resources.");
    }

    public void printMessage() {
        System.out.println("Hello");
    }

}

Create Config

package com.knf.dev.demo;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan
public class Config {

}

Spring provides a mechanism to identify application component explicitly through the @ComponentScan annotation. We are not passing arguments to @ComponentScan, letting Spring to scan the current package and all of its sub-packages.

Create main class - Application.java 

package com.knf.dev.demo;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;

public class Application {
    
    public static void main(String[] args) {
        
        AbstractApplicationContext  context = 
                new AnnotationConfigApplicationContext(Config.class);
        MyComponent myComponent = context.getBean(MyComponent.class);
        myComponent.printMessage();
        
        context.close();
    }
}

The AbstractApplicationContext.close() method will close the application context, destroying all cached singleton beans and perform finalization like calling the destroy methods. 

Console Output: 

Perform initialization task.

Hello

Perform destructive task or release resources.

Source code  

https://github.com/knowledgefactory4u/spring-core-examples

Are you preparing for Spring certification or preparing for Spring interview? Then below examples are interesting for you!

Spring Core Annotations

• Spring @Qualifier Annotation Example

• Spring @Autowired Annotation Example

• Spring @Value Annotation Example

• Spring @Scope Annotation Example

• Spring @Bean Annotation Example

• Spring @Primary Annotation Example

• Spring @ImportResource Annotation Example

• Spring @LookUp Annotation Example

• Spring @Lazy Annotation Example

• Spring @PropertySource Annotation Example

• Spring @DependsOn Annotation Example

• Spring @Import Annotation Example