What are spring beans? | Spring Tutorial | Spring basics | Spring Framework

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Introduction

In the Spring Framework, Spring Beans are the backbone of your application. A Spring Bean is simply an object that is instantiated, assembled, and managed by the Spring IoC (Inversion of Control) container.

Instead of manually creating objects using the new keyword, the Spring container takes over the complete lifecycle of beans—from creation and dependency injection to destruction—enabling loose coupling and easy maintenance.

Ways to Define Spring Beans

Spring provides multiple ways to define and configure beans:

• XML Configuration: Defined using the <bean> tag inside <beans>.
• Annotation Configuration: Defined using annotations like @Component, @Service, @Repository, or @Controller.
• Java-Based Configuration: Defined using @Configuration and @Bean annotations in pure Java classes.

1. Create the Java Bean Class

Here is a simple POJO class named Employee with a name property, setter method, and a display method:

public class Employee {
    private String name;

    public void setName(String name) {
        this.name = name;
    }

    public void displayEmployeeDetails() {
        System.out.println("Employee Name: " + name);
    }
}
  

2. Configure the Bean in Spring XML

In your Spring configuration file (applicationContext.xml), define the bean using the <bean> element, giving it a unique id and configuring its properties:

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans 
       http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="employeeBean" class="Employee">
        <property name="name" value="Peter" />
    </bean>

</beans>
  

3. Retrieve the Bean from the Spring Container

Load the application context and retrieve the managed bean using its unique ID:

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Employee emp = (Employee) context.getBean("employeeBean");
        emp.displayEmployeeDetails();
    }
}
  

Watch More Spring Tutorials

• How to Inject String value using Spring dependency injection by constructor? | Spring Tutorial
• How to Inject Dependent Object using Spring dependency injection by constructor? | Spring Tutorial
• In-Depth Comparison: Constructor Injection vs. Setter Injection in Java | Spring Tutorial

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What are spring beans? | Spring Tutorial | Spring basics | Spring Framework

What are spring beans? | Spring Tutorial | Spring basics | Spring Framework

What are spring beans? | Spring Tutorial | Spring basics | Spring Framework

What are spring beans? | Spring Tutorial | Spring basics | Spring Framework