Spring Part 01 - IOC

Spring - Inversion of Control 

Sample Program to create object and call method without using 'Spring Framework'

package com.ah.ioc;

public class Test {
    public static void main(String[] args) {
        SamsungMobile sm = new SamsungMobile();
        sm.display();
    }
}

package com.ah.ioc;

public class SamsungMobile implements Mobile{
    public SamsungMobile(){
        System.out.println("Constructor of SamsungMobile class");
    }

    public void display(){
        System.out.println("display() method in SamsungMobile class");
    }
}

Maven Dependency:

<dependency>

  <groupId>org.springframework</groupId>

  <artifactId>spring-context</artifactId>

  <version>5.3.16</version>

</dependency>

Sample Program to create object and call method using 'Spring Framework' 

package com.ah.ioc;

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

public class Test {
    public static void main(String[] args) {
        ApplicationContext context =
                new ClassPathXmlApplicationContext("beans_ioc.xml");
        SamsungMobile samsungMobile = context.getBean("sm", SamsungMobile.class);
        samsungMobile.display();
    }

} 

package com.ah.ioc;

public class SamsungMobile implements Mobile{
    public SamsungMobile(){
        System.out.println("Constructor of SamsungMobile class");
    }

    public void display(){
        System.out.println("display() method in SamsungMobile class");
    }
}

beans_ioc.xml

<?xml version="1.0" encoding="UTF-8"?>
<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="sm" class="com.ah.ioc.SamsungMobile"/>
</beans>

Sample Program using interface 'Spring Framework'

package com.ah.ioc;

public interface Mobile {
    public void display();
}

package com.ah.ioc;

public class SamsungMobile implements Mobile{
    public SamsungMobile(){
        System.out.println("Constructor of SamsungMobile class");
    }

    public void display(){
        System.out.println("display() method in SamsungMobile class");
    }
}

package com.ah.ioc;

public class NokiaMobile implements Mobile{
    public NokiaMobile(){
        System.out.println("Constructor of NokiaMobile class");
    }

    public void display(){
        System.out.println("display() method in NokiaMobile class");
    }
}

package com.ah.ioc;

public class ABCMobile implements Mobile{
    public ABCMobile(){
        System.out.println("Constructor of ABCMobile class");
    }

    public void display(){
        System.out.println("display() method in ABCMobile class");
    }
}

package com.ah.ioc;

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

public class Test {
    public static void main(String[] args) {

        ApplicationContext context =
                new ClassPathXmlApplicationContext("beans_ioc.xml");
        Mobile mobile = context.getBean("mobile", Mobile.class);
        mobile.display();
    }
}

beans_ioc.xml

<?xml version="1.0" encoding="UTF-8"?>
<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="mobile" class="com.ah.ioc.ABCMobile"/>
</beans>

Watch Demo