Lazy Bean 

Spring Inversion of Control (IoC) also known as Dependency Injection (DI) is a process by which objects define their dependencies with collaborating objects. The following example shows a lazy initialized bean. The first bean (lazy1) being singleton is initialized during ApplicationContext initialization. Though the second bean (lazy2) is singleton it is not initialized as part of ApplicationContext initialization because its lazy-init attribute is set to true.

File Name  :   /SpringCore001/conf/lazy/lazy_basic.xml

view sourceprint? 01 <?xml version="1.0" encoding="UTF-8"?> 02 <beans xmlns="http://www.springframework.org/schema/beans" 03        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 04        xsi:schemaLocation="http://www.springframework.org/schema/beans 05            http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> 06   07     <bean id="lazy1" class="com.bethecoder.tutorials.spring3.basic.LazyBean"> 08         <constructor-arg value="Non Lazy" /> 09     </bean> 10   11     <bean id="lazy2" class="com.bethecoder.tutorials.spring3.basic.LazyBean" lazy-init="true"> 12         <constructor-arg value="Lazy" /> 13     </bean> 14     15 </beans>

File Name  :   com/bethecoder/tutorials/spring3/basic/LazyBean.java

package com.bethecoder.tutorials.spring3.basic; public class LazyBean {   public LazyBean(String name) {     System.out.println("In Constructor : " + name);   } }

File Name  :   com/bethecoder/tutorials/spring3/tests/lazy/BasicTests.java  Author  :   Sudhakar KV Email  :   kvenkatasudhakar@gmail.com

package com.bethecoder.tutorials.spring3.tests.lazy; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.bethecoder.tutorials.spring3.basic.LazyBean; public class BasicTests {   /**    * @param args    */   public static void main(String[] args) {          System.out.println("Initializing ApplicationContext");     ApplicationContext factory = new ClassPathXmlApplicationContext("lazy_basic.xml");     System.out.println("ApplicationContext Initialized");          System.out.println("Accessing lazy1");     LazyBean lazy1 = (LazyBean) factory.getBean("lazy1");     System.out.println(lazy1);     System.out.println("Accessing lazy2");     LazyBean lazy2 = (LazyBean) factory.getBean("lazy2");     System.out.println(lazy2);   } }

Initializing ApplicationContext
In Constructor : Non Lazy
ApplicationContext Initialized

Accessing lazy1
com.bethecoder.tutorials.spring3.basic.LazyBean@db4fa2

Accessing lazy2
In Constructor : Lazy
com.bethecoder.tutorials.spring3.basic.LazyBean@1e0f2f6