Why destroy-method is giving error in Spring MVC? - spring

Question

I have destroy method in my bean but it is not showing in the out put. Could you please help me here.
package com.vaannila;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class HelloWorldApp {
public static void main(String[] args) {
AbstractApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
Ticket helloWorld = (Ticket) context.getBean("ticket");
helloWorld.setTicketNo("ABC009");
helloWorld.display();
context.close();
}
}
below is my xml file
<?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="helloWorld" class="com.vaannila.HelloWorld">
<property name="message" value="Hello World!"></property>
</bean>
<bean id="ticket" class="com.vaannila.Ticket"
scope="prototype" init-method="init" destroy-method="destroy"/>
</beans>
and Ticket class is below
package com.vaannila;
public class Ticket {
private String ticketNo="";
public String getTicketNo() {
return ticketNo;
}
public void setTicketNo(String ticketNo) {
this.ticketNo = ticketNo;
}
public void display()
{
System.out.println("Your Ticket No. is"+ ticketNo);
}
public void init()
{
System.out.println("Bean is ready You can use it now");
}
public void destroy()
{
System.out.println("Bean is going to destroy");
}
}
The out put is giving for init method but not for destroy method..
If i changed the init-method and destroy-method as default as below it is giving error in destroying the bean called "helloWorld"
<?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"
default-init-method="init" default-destroy-method="destroy">
<bean id="helloWorld" class="com.vaannila.HelloWorld">
<property name="message" value="Hello World!"></property>
</bean>
<bean id="ticket" class="com.vaannila.Ticket"
scope="prototype"/>
</beans>

Answer 1

When a bean is defined as prototype, the bean container creates new instances of this been whenever it is asked for that bean. That's the idea behind prototype-scoped beans.
After they are created, the container gives up responsibility for the bean. It cannot know if you are still holding a reference to it, or when is the moment you drop the last reference. This is true even after the container is closed. (The container is not the garbage collector.) So it cannot possibly know when is the right moment to call the destroy method.
If you need deinitialization for your ticket, you will have to call such a method from your code directly I think (assuming that it makes no sense to have singleton tickets).