Spring - Bean Scopes

When defining a in Spring, you have the option of declaring a scope for that bean.

For example, To force Spring to produce a new bean instance each time one is needed, you should declare the bean's scope attribute to be prototype.

Similar way if you want Spring to return the same bean instance each time one is needed, you should declare the bean's scope attribute to be singleton.

The Spring Framework supports following five scopes, three of which are available only if you use a web-aware ApplicationContext:

singleton

This scopes the bean definition to a single instance per Spring IoC container (default).

prototype.

This scopes a single bean definition to have any number of object instances.

request

This scopes a bean definition to an HTTP request. Only valid in the context of a web-aware Spring ApplicationContext.

session

This scopes a bean definition to an HTTP session. Only valid in the context of a web-aware Spring ApplicationContext.

global-session

This scopes a bean definition to a global HTTP session. Only valid in the context of a web-aware Spring ApplicationContext.

The Singleton scope:

HelloWorld.java

package com.jtc;
public class HelloWorld {
private String message;
public void setMessage(String message){
this.message = message;
}
public void getMessage(){
System.out.println("Your Message : " + message);
}
}

MainApp.java

package com.jtc;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class MainApp {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
HelloWorld objectA = (HelloWorld) context.getBean("helloWorld");
objectA.setMessage("I am object A");
objectA.getMessage();
HelloWorld objectB = (HelloWorld) context.getBean("helloWorld");
objectB.getMessage();
}
}

Beans.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-3.0.xsd">
   <bean id=
   "helloWorld" 
   class="com.jtc.HelloWorld"scope="singleton"
   >
       <property name
	   ="message" value=
	   "Hello World!"/>
   </bean>
</beans>

Add Below Libraries

commons-logging-1.1.1
spring-aop-4.1.6.RELEASE
spring-aspects-4.1.6.RELEASE
spring-beans-4.1.6.RELEASE
spring-context-4.1.6.RELEASE
spring-context-support-4.1.6.RELEASE
spring-core-4.1.6.RELEASE
spring-expression-4.1.6.RELEASE
spring-instrument-4.1.6.RELEASE
spring-instrument-tomcat-4.1.6.RELEASE
spring-jdbc-4.1.6.RELEASE
spring-jms-4.1.6.RELEASE
spring-messaging-4.1.6.RELEASE
spring-orm-4.1.6.RELEASE
spring-oxm-4.1.6.RELEASE
spring-test-4.1.6.RELEASE
spring-tx-4.1.6.RELEASE
spring-web-4.1.6.RELEASE
spring-webmvc-4.1.6.RELEASE
spring-webmvc-portlet-4.1.6.RELEASE
spring-websocket-4.1.6.RELEASE

OutPut

Your Message : I am object A
Your Message : I am object A

The Prototype scope:

You need to change only Beans.xml and set scope="prototype" then output will be: OutPut

Your Message : I am object A
Your Message : null

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Spring - Bean Scopes

The Spring Framework supports following five scopes, three of which are available only if you use a web-aware ApplicationContext:

The Singleton scope:

The Prototype scope: