Since J2EE Servlet v2.3, there's an easy, standard way to hook in your initialization at deployment time.  You simply write a [[http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/ServletContextListener.html|ServletContextListener]] and reference it in your web.xml with
{{{
  <listener>
    <listener-class>
      com.idiacomputing.startup.StartupServletContextListener
    </listener-class>
  </listener>
}}}

S''''''ervletContextListener defines two method signatures, contextInitialized and contextDestroyed.  Both are passed a [[http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/ServletContextEvent.html|ServletContextEvent]] containing the S''''''ervletContext of your webApp.

The [[http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/ServletContext.html|ServletContext]] contains such goodies as the context-param elements of the web.xml file
{{{
    private void extractServletContextParameters(Map nameValuePairs, ServletContext servletContext) {
        Enumeration parmEnum = servletContext.getInitParameterNames();
        while (parmEnum.hasMoreElements()) {
            String name = (String) parmEnum.nextElement();
            String value = servletContext.getInitParameter(name);
            nameValuePairs.put(name, value);
        }
    }
}}}

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See also
 * http://e-docs.bea.com/wls/docs81/webapp/app_events.html#175768