How to set a default method to running code on the creation or destruction of a bean

In the post Executing code on the creation or destruction of a bean in Spring I explain three ways to execute code on the creation or destruction of a Bean in Spring.
With two of these ways you can set the execution of a specific custom method:

• with the annotations @PostConstruct and @PreDestroy
• configuring the properties init-method and destroy-method

There is a very convenient way in the case that more beans have methods with the same name to be executed on their creation and destruction, i.e. you can specify a default method for all the beans.

For example see the following java project:

1. create the file conf/app-context.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" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd" default-lazy-init="true" default-init-method="defaultInit" default-destroy-method="defaultDestroy" > <context:annotation-config/> <bean id="simpleBean" class="eu.lucazanini.mybean.SimpleBean" scope="singleton" /> </beans>

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   ]<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xmlns:context="http://www.springframework.org/schema/context"     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd"     default-lazy-init="true"     default-init-method="defaultInit"     default-destroy-method="defaultDestroy" >   <context:annotation-config/>       <bean id="simpleBean" class="eu.lucazanini.mybean.SimpleBean" scope="singleton" />   </beans>

   
   where the default methods are set in the highlighted lines;
   the folder “conf” must be in the classpath
2. create the file conf/log4j.xml
   
   XHTML

   <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE log4j:configuration PUBLIC "-//LOGGER" "log4j.dtd"> <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/"> <appender name="stdout" class="org.apache.log4j.ConsoleAppender"> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%d %-5p %c{1}:%L %m %n" /> <!-- ConversionPattern format specification %d inserts the date; you can specify the format (%d{yyyy-MM-dd HH:mm:ss,SSS}) %-5p inserts the priority log level, 5 characters, left justified %c{1} inserts the name of the class %L inserts the line number %m inserts the user message %n inserts the separator (for example, a new line) --> </layout> </appender> <appender name="fileAppender" class="org.apache.log4j.RollingFileAppender"> <param name="append" value="false" /> <param name="Threshold" value="DEBUG" /> <param name="File" value="logs/app.log"/> <param name="MaxFileSize" value="512KB" /> <param name="MaxBackupIndex" value="10" /> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%d %-5p %c{1}:%L %m %n" /> </layout> </appender> <!--sets the priority log level for org.springframework--> <logger name="org.springframework"> <level value="info"/> </logger> <!--sets the priority log level for eu.lucazanini--> <logger name= "eu.lucazanini"> <level value="debug"/> </logger> <!--sets the default priority log level--> <root> <priority value="debug"></priority> <appender-ref ref="stdout"/> <appender-ref ref="fileAppender"/> </root> </log4j:configuration>

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   <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE log4j:configuration PUBLIC "-//LOGGER" "log4j.dtd">   <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">     <appender name="stdout" class="org.apache.log4j.ConsoleAppender">         <layout class="org.apache.log4j.PatternLayout">             <param name="ConversionPattern" value="%d %-5p %c{1}:%L %m %n" /> <!-- ConversionPattern format specification %d      inserts the date; you can specify the format (%d{yyyy-MM-dd HH:mm:ss,SSS}) %-5p    inserts the priority log level, 5 characters, left justified %c{1}   inserts the name of the class %L      inserts the line number %m      inserts the user message %n      inserts the separator (for example, a new line) -->         </layout>     </appender>       <appender name="fileAppender" class="org.apache.log4j.RollingFileAppender">      <param name="append" value="false" />         <param name="Threshold" value="DEBUG" />         <param name="File" value="logs/app.log"/>         <param name="MaxFileSize" value="512KB" />         <param name="MaxBackupIndex" value="10" />         <layout class="org.apache.log4j.PatternLayout">             <param name="ConversionPattern" value="%d %-5p %c{1}:%L %m %n" />         </layout>     </appender>   <!--sets the priority log level for org.springframework-->     <logger name="org.springframework">         <level value="info"/>     </logger>   <!--sets the priority log level for eu.lucazanini-->     <logger name= "eu.lucazanini">         <level value="debug"/>     </logger>   <!--sets the default priority log level-->     <root>         <priority value="debug"></priority>         <appender-ref ref="stdout"/>         <appender-ref ref="fileAppender"/>     </root> </log4j:configuration>

3. create the file eu/lucazanini/mybean/Main.java
   
   Java

   package eu.lucazanini.mybean; import org.apache.log4j.Logger; import org.springframework.context.support.*; public class Main { private static org.apache.log4j.Logger log = Logger.getLogger(Main.class); public static void main(String[] args) { GenericXmlApplicationContext ctx = new GenericXmlApplicationContext(); ctx.load("classpath:app-context.xml"); ctx.refresh(); log.debug("creating bean"); SimpleBean bean = (SimpleBean) ctx.getBean("simpleBean"); log.debug("created bean"); log.debug("destroying bean"); ctx.destroy(); log.debug("destroyed bean"); log.debug("application shutdown"); } }

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   package eu.lucazanini.mybean;   import org.apache.log4j.Logger; import org.springframework.context.support.*;   public class Main {       private static org.apache.log4j.Logger log = Logger.getLogger(Main.class);       public static void main(String[] args) {   GenericXmlApplicationContext ctx = new GenericXmlApplicationContext(); ctx.load("classpath:app-context.xml"); ctx.refresh();   log.debug("creating bean"); SimpleBean bean = (SimpleBean) ctx.getBean("simpleBean"); log.debug("created bean");   log.debug("destroying bean"); ctx.destroy(); log.debug("destroyed bean");   log.debug("application shutdown");     } }

4. create the file eu/lucazanini/mybean/SimpleBean.java
   
   ]package eu.lucazanini.mybean; import org.apache.log4j.Logger; public class SimpleBean { private static org.apache.log4j.Logger log = Logger .getLogger(SimpleBean.class); public SimpleBean() { log.debug("constructor"); } public void defaultInit() { log.debug("defaultInit-method"); } public void defaultDestroy() { log.debug("defaultDestroy-method"); } }

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   ]package eu.lucazanini.mybean;   import org.apache.log4j.Logger;   public class SimpleBean {       private static org.apache.log4j.Logger log = Logger     .getLogger(SimpleBean.class);       public SimpleBean() { log.debug("constructor");     }       public void defaultInit() { log.debug("defaultInit-method");     }       public void defaultDestroy() { log.debug("defaultDestroy-method");     }   }

   
   where the default methods are highlighted

The output is the following: