Question

I know this question is a duplicate of Execute method on startup in spring. however I have tried the advice posted in the accepted answer for that question, and nothing has worked for me. As such, I suspect that although it is the same question being asked here, I strongly feel that the root cause is different and thus requires a different answer/solution.

I am trying to get Spring to create a bean at start up and immediately execute one of its methods.

My spring config (heartbeat-config.xml):

<beans (all the xmlns stuff here ommitted for brevity)>
    <bean id="heartbeat" class="org.me.heartbeat.Heartbeat"/>
</beans>

And Heartbeat.java:

public class Heartbeat
{
    @PostConstruct
    public void start()
    {
        System.out.println("I should see this message in the logs somewhere!!");
    }
}

And finally, my web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app
    xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
    version="2.4">

    <!-- The display name of this web application -->
    <display-name>Heartbeat</display-name>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/heartbeat-config.xml</param-value>
    </context-param>

    <listener>
        <listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
    </listener>
</web-app>

When I run this in Tomcat I don’t get any startup errors. Tomcat looks like its running healthy (as I can tell from the logs). I do not, however, see any output in the logs that should be generated by the System.out invocation in my start() method (Tomcat redirects all standard output to its log files).

Am I overlooking something here? Is there an obvious diagnosis I could be performing?

Answer 1

The most simple way to do that is to forget about annotations and change your bean definition to:

<bean id="heartbeat" class="org.me.heartbeat.Heartbeat" init-method="start"/>

If you want annotations you need to declare the context namespace and put this int your applicationContext.xml:

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       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
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context-2.5.xsd">

    <!-- Enable @PostConstruct, @PreDestroy and friends in Spring -->
    <context:annotation-config/>

    <bean id="heartbeat" class="org.me.heartbeat.Heartbeat"/>
</beans>

Note: check the namespaces, they are copypasted from the net.