What are Spring Bean Configurations?

Introduction

Java is one of the most popular programming languages worldwide, powering everything from enterprise software to mobile applications. Whether you are a beginner or an experienced programmer, mastering Java can open doors to lucrative career opportunities. In this guide, we explore the essentials of Java programming, the importance of Java certification, and the best ways to learn Java online.

Spring Bean are the objects that are managed by Spring IoC and are also acts as a backbone of an application. There are three methods which provide configuration metadata to Spring Container:

XML Based Configuration: Configuration XML file is used to create Beans.
Annotation Based Configuration: By using annotations like @Service, @Component, @Scope.
Java Based Configuration: By using @Configuration, @ComponentScan, @Bean.

XML Spring Bean Based Configuration:

Here we will use XML configuration to define beans. For this we need three maven dependencies:

spring-core: It contains the most basic classes required, which are required to work with Spring modules.

Spring Bean: It provides org.springframework.beans.factory.BeanFactory interface that is required for Spring beans.

spring-context: It provides org.springframework.context.ApplicationContext interface, which is required for additional features like bean lifecycle event listeners, AOP capabilities, etc.

Step 1: Create a maven dependency file pom.xml

<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.google.webmvc</groupId>
    <artifactId>SpringDemos</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging> 
    <name>SpringDemos</name>
    <url>http://maven.apache.org</url> 
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring.version>5.2.0.RELEASE</spring.version>
    </properties>
 
    <dependencies>
        <!-- Spring Dependencies -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
    </dependencies>
</project>

Step 2: Define all the Spring beans in a single configuration file

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="https://www.springframework.org/schema/beans"
    xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xmlns:context="https://www.springframework.org/schema/context"
    xsi:schemaLocation="https://www.springframework.org/schema/beans 
    https://www.springframework.org/schema/beans/spring-beans.xsd 
    https://www.springframework.org/schema/context 
    https://www.springframework.org/schema/context/spring-context.xsd"> 
    <bean id="operations"    class="com.google.spring.beans.Operations"></bean>
    <bean id="employee" class="com.google.spring.beans.Employee"></bean>
    <bean id="department"    class="com.google.spring.beans.Department"></bean>
</beans>

Step 3: Define all the beans in multiple configuration files and import the main xml file.

employee.xml

<beans>
    <bean id="employee" class="com.google.spring.beans.Employee"></bean> 
</beans>

department.xml

<beans> 
    <bean id="department" class="com.google.spring.beans.Department"></bean> 
</beans>

beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans> 
    <import resource="employee.xml"/>
    <import resource="department.xml"/> 
    <bean id="operations" class="com.google.spring.beans.Operations"></bean> 
</beans>

Step 4: Create a main java file

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; 
public class XmlConfigExample 
{
    public static void main( String[] args )
    {
    @SuppressWarnings("resource")
    ApplicationContext ctx = new
                  ClassPathXmlApplicationContext( "com/google/core/demo/beans/beans.xml" ); 
        Employee employee = ctx.getBean(Employee.class); 
        Department department = ctx.getBean(Department.class); 
        Operations operations = ctx.getBean(Operations.class); 
        System.out.println(department);
        System.out.println(employee); 
        operations.helloWorld();
    }
}

Java Based Configuration:

Spring Beans can be created using java configuration using annotations like @Bean, @ComponentScan, and @Configuration.

Component Scanning can be done in two steps:

Using one of the four annotations: @Component, @Repository, @Service, @Controller.

EmployeeManagerImpl.java

import org.springframework.stereotype.Service;
import com.google.spring.model.Employee;
import com.google.spring.service.EmployeeManager; 
@Service
public class EmployeeManagerImpl implements EmployeeManager { 
    @Override
    public Employee create() {
        Employee emp =  new Employee();
        emp.setId(1);
        emp.setName("ABC");
        return emp;
    }
}

Including Bean Packages in @ComponentScan

AppConfig.java

@Configuration
@ComponentScan(basePackages = "com.google.spring.service")
public class AppConfig { 
}

Example:

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.google.spring.model.Employee;
import com.google.spring.service.EmployeeManager; 
public class Main 
{
    public static void main( String[] args )
    {
        //Method 1
        //ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class); 
        //Method 2
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
        ctx.register(AppConfig.class);
        ctx.refresh(); 
        EmployeeManager empManager = ctx.getBean(EmployeeManager.class);
        Employee emp = empManager.create(); 
        System.out.println(emp);
    }
}

Spring Bean application can also be created using @Bean and @Configuration annotations.

Step 1: Create a Java Bean Class

EmployeeManagerImpl.java

public class EmployeeManagerImpl implements EmployeeManager {
 
    @Override
    public Employee create() {
        Employee emp =  new Employee();
        emp.setId(1);
        emp.setName("ABC");
        return emp;
    }
}

Step 2: Create @Bean class

AppConfig.java

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.google.spring.service.EmployeeManager;
import com.google.spring.service.impl.EmployeeManagerImpl; 
@Configuration
public class AppConfig { 
    @Bean
    public EmployeeManager employeeManager() {
        return new EmployeeManagerImpl();
    } 
}

Example:

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.google.spring.model.Employee;
import com.google.spring.service.EmployeeManager;
 
public class Main 
{
    public static void main( String[] args )
    {
        //Method 1
        //ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class); 
        //Method 2
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
        ctx.register(AppConfig.class);
        ctx.refresh(); 
        EmployeeManager empManager = ctx.getBean(EmployeeManager.class);
        Employee emp = empManager.create(); 
        System.out.println(emp);
    }
}

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1. High Demand in the Industry

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Java follows the principle of “Write Once, Run Anywhere (WORA),” making it a versatile choice for software development across different platforms.

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4. Career Growth and Salary Benefits

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Java Programming: A Beginner-Friendly Approach

1. Understanding Java Basics

Java follows an object-oriented programming (OOP) approach, making it easier to develop modular and scalable applications. Key concepts include:

Classes and Objects
Encapsulation, Inheritance, and Polymorphism
Data Types and Variables
Control Statements (Loops, Conditional Statements)
Methods and Functions

2. Java Development Environment

To start coding in Java, you need:

JDK (Java Development Kit)
An IDE (Integrated Development Environment) like Eclipse or IntelliJ IDEA
Basic knowledge of command-line tools

3. Writing Your First Java Program

Here’s a simple Java program to print “Hello, World!”:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Run this program in an IDE or command line, and you are officially a Java programmer!

Java Certification: Why It Matters

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Popular Java certifications include:

Oracle Certified Associate (OCA) – Java SE
Oracle Certified Professional (OCP) – Java SE
Oracle Certified Master (OCM) – Java SE

3. Competitive Edge in the Job Market

Certified Java professionals often receive higher salaries and better job opportunities than non-certified candidates.

Learning Java Online: The Best Approach

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Hands-on projects
Experienced instructors
Industry-recognized certification
24/7 student support

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Real-World Applications of Java

1. Web Development

Java is widely used in web applications, frameworks like Spring Bean Boot simplify web development.

2. Mobile App Development

Android apps are built using Java, making it essential for mobile developers.

3. Enterprise Applications

Java is the backbone of enterprise-level software due to its scalability and security.

4. Game Development

Many popular games, including Minecraft, are developed using Java.

Key Takeaways

Java is a versatile and in-demand programming language.
A Java certification enhances job prospects and salary potential.
Online courses, such as those from H2K Infosys, provide flexible and hands-on learning.
Java has numerous real-world applications, including web, mobile, and enterprise development.

Conclusion

Spring Bean configurations are essential for managing the lifecycle and dependencies of beans in a Spring application. They define how objects are created, wired, and managed by the Spring Bean container. Spring offers multiple ways to configure beans, including XML configuration, Java-based configuration using @Configuration and @Bean, and annotation-based configuration with @Component, @Service, and @Repository. The choice of configuration depends on project requirements, but Java-based and annotation-driven approaches are widely preferred for their simplicity and maintainability. Properly configuring beans ensures a well-structured, modular, and scalable Spring Bean application.

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