Spring lifetime callbacks

This is 13 of 16 parts of tutorial series

Tutorial Content:

The Spring Framework provides several callback interfaces to change the behavior of your bean in the container; they include InitializingBean and DisposableBean.

The life cycle of a Spring bean is easy to understand. When a bean is instantiated, it may be required to perform some initialization to get it into a usable state. Similarly, when the bean is no longer required and is removed from the container, some cleanup may be required.

Initialization callbacks:

Implementing the org.springframework.beans.factory.InitializingBean interface allows a bean to perform initialization work after all necessary properties on the bean have been set by the container. The InitializingBean interface specifies exactly one method:

Generally, the use of the InitializingBean interface can be avoided and is actually discouraged since it unnecessarily couples the code to Spring.You have to use  afterPropertiesSet(),you can not change name of method.There is alternative for this i.e. XML-based configuration metadata.This is done using the 'init-method' attribute of tag.It provides flexibility of changing method name.

…is exactly the same as…

… but does not couple the code to Spring.

Destruction callbacks:

Implementing the org.springframework.beans.factory.DisposableBean interface allows a bean to get a callback when the container containing it is destroyed. The DisposableBean interface specifies a single method:

 Generally, the use of the DisposableBean interface can be avoided and is actually discouraged since it unnecessarily couples the code to Spring.You have to use  destroy(),you can not change name of method.There is alternative for this i.e. XML-based configuration metadata.This is done using the 'destroy-method' attribute of tag.It provides flexibility of changing method name.

…is exactly the same as…

… but does not couple the code to Spring.

Spring lifetime callbacks Example:

For configuring spring in your eclipse ide please refer  hello world example

1.Country.java

This is simple pojo class having some attributes so here country has name.
Create Country.java under package org.arpit.javapostsforlearning.Copy following content into Country.java.

2.ApplicationContext.xml

3.LifetimeCallbacksMain.java

This class contains main function.Create LifetimeCallbacksMain.java under package org.arpit.javapostsforlearning.Copy following content into LifetimeCallbacksMain.java

Here you need to register a shutdown hook registerShutdownHook() method that is declared on the AbstractApplicationContext class. This will ensures a graceful shutdown and calls the relevant destroy methods.

4.Run it

When you will run above application,you will get following as output.

Default Initialization and destroy method:

If you have too many beans having initialization and or destroy methods with the same name, you don’t need to declare init-method and destroy-method on each individual bean. Instead framework provides the flexibility to configure such situation using default-init-method and default-destroy-method attributes on the element as follows:

That’s all about Spring lifetime callbacks.


import_contacts

You may also like:

Related Posts

  • 24 June

    No qualifying bean of type in Spring or Spring Boot

    In this post, we will see about an exception: No qualifying bean of type. Exceptions are least expected but you might get it while working with Spring. or Spring boot. Did you get this exception: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type? If yes, let’s see different reasons for it. Reason 1: You forgot to declare […]

  • 17 June

    Spring XML configuration example

    In this post, we will see how to create Spring hello world XML based configuration example. Here are simple steps to create Spring XML configuration example. 1. Create a simple java maven project. 2. Maven dependency put spring and cglib maven dependency in pom.xml. [crayon-600ba180695cd313311860/] So your pom.xml will look like: [crayon-600ba180695d1241762954/] 3. Create Bean class […]

  • 15 June

    Injecting Prototype bean into a Singleton bean in Spring

    In this post, we will see how to inject prototype bean scope into Singleton Instance in Spring. This is one of the most asked Spring interview questions. Problem When you inject prototype bean to singleton bean, prototype bean still behave like a singleton bean. Let’s understand this with the help of example. 1. Create a […]

  • 15 June

    Circular dependencies in Spring

    In this post, we will discuss one of the most asked Spring interview questions. What happens if there are circular dependencies in Spring. Problem What if there are circular dependencies in Spring? For example: Class A requires an instance of Class B and Class B requires an instance of Class A. Let’s create an example […]

  • 12 September

    Spring init-method and destroy-method example

    In this post, we will see about Spring init-method and destroy-method. When bean is instantiated or destroyed , there are some operations you may need to perform, so you can use init-method and destroy-method to call this methods while bean is being created or destroyed. Lets understand it with the help of simple example: For […]

  • 27 July

    Prefix “context” for element “context:component-scan” or “context:annotation-config” is not bound : Spring error

    When you are working on spring or spring mvc application, you may encounter below error message. org.xml.sax.SAXParseException: The prefix “context” for element “context:component-scan” is not bound . or org.xml.sax.SAXParseException: The prefix “context” for element “context:annotation-config” is not bound . This issue generally occurs when you do not include context namespace. For example: Lets say you have below […]

Leave a Reply

Your email address will not be published. Required fields are marked *

Subscribe to our newletter

Get quality tutorials to your inbox. Subscribe now.