How to load config.properties file in jboss-tomcat-struts when server starts

I'm Java EE beginner. I'm trying to modify a system (jboss-3.2.3, tomcat-5.0.28, struts-1.1). I need to load a config.properties file when jboss/tomcat starts, so, the properties could be available for the entire application.

This is what I was asked to do: "Load the .properties the first time (only one time) so, when it need to be readed is already in memory".

How can I do that? Where can I start?

EDIT: I trying to load from properties-service.xml

<?xml version="1.0" encoding="UTF-8"?>
<server>
    <mbean code="org.jboss.varia.property.PropertyEditorManagerService" name="jboss:type=Service,name=PropertyEditorManager"></mbean>

    <mbean code="org.jboss.varia.property.SystemPropertiesService" name="jboss:type=Service,name=SystemProperties">
        <attribute name="URLList">
            ./c开发者_如何学运维onf/somelocal.properties
        </attribute>
        <attribute name="Properties">
            my.project.property=This is the value of my property
            my.project.anotherProperty=This is the value of my other property
        </attribute>
    </mbean>
</server>

Looks like JBOSS loads correctly:

2011-08-01 11:54:29,736 [INFO ] property.SystemPropertiesService - Loaded system properties from: file:/D:/jboss-3.2.3/server/default/conf/somelocal.properties
2011-08-01 11:54:29,736 [INFO ] property.PropertyEditorManagerService - Started jboss:type=Service,name=PropertyEditorManager
2011-08-01 11:54:29,736 [INFO ] property.SystemPropertiesService - Started jboss:type=Service,name=SystemProperties

But when I tried to use the property returns null:

String myProperty = System.getProperty("my.project.property");
System.out.println(myProperty); // null

What could be wrong?

Take a look at the JBoss System Properties Service. The configuration is in <jboss-home>/server/<server-name>/deploy/properties-service.xml. Here's an example:

<server>
    <mbean code="org.jboss.varia.property.SystemPropertiesService"
           name="jboss.util:type=Service,name=SystemProperties">

        <!-- Load properties from each of the given comma seperated URLs -->
        <attribute name="URLList">
            http://somehost/some-location.properties,
            ./conf/somelocal.properties
        </attribute>

        <!-- Set propertuies using the properties file style. -->
        <attribute name="Properties">
            property1=This is the value of my property
            property2=This is the value of my other property
        </attribute>

    </mbean>
</server>