Spring JSR 250 Annotations

Tutorial Content: Spring tutorial for beginners

Spring supports JSR 250 Annotations such as @PostConstruct, @PreDestroy and @Resource annotations.Lets  discuss each in brief.

@Resource:

Spring also supports injection using the JSR-250 @Resource annotation on fields or bean property setter methods. This is a common pattern found in Java EE 5 and Java 6 which Spring supports for Spring-managed objects as well.
@Resource takes name as attribute and by default Spring will interpret that value as the bean name to be injected. In other words, it follows by-name semantics.If you do not specify name attribute then it will interpret property name as bean name to be injected and then it will search in XML configuration file.

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 and object of Capital class.
Create Country.java under package org.arpit.javapostsforlearning.Copy following content into Country.java.

2.Capital.java

This is also simple pojo class having one attribute called “capitalName”.

Create Capital.java under package org.arpit.javapostsforlearning.java.Above Country class contains object of this class.Copy following content into Capital.java

3.QualifierAnnotationInSpringMain.java

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

4.ApplicationContext.xml


As you can note here we are having two beans of same type.In Country.java we have used @Resource(name-“capitalA”) it means we want to autowire capital property of country with bean id=”capitalA” in XML configuration file.

5.Run it:

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

@PostContruct and @PreDestroy:

These annotations are alternative methods for defining initialization and destruction callback functions.
We have used all other method in 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.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.

3.ApplicationContext.xml

4.Run it

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

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