Jonathan Lalou's blog

Case

You would like to set a System property within an application packaged as a WAR.
Of course, you may modify the launching scripts of your servers, to add an option -DmyPropertyName=myPropertyValue. Sometimes, you would like to avoid such a solution, because updating the property would require an update of the setEnv.* files and therefore a action of the exploitation team.

In my case, I had to set the property tangosol.coherence.cacheconfig, which hints at the configuration file used my Oracle Coherence / Coherence*Web

Fix

The first solution is to set the property in a startup class. For more detials, consult this page: WebLogic: use a startup and/or a shutdown class in a WAR.

Another mean to handle this problematic is to create a servlet, with a code similar to:

public class JonathanBootServlet extends HttpServlet {
    private static final Logger LOGGER = Logger.getLogger(JonathanBootServlet.class);
    private static final String SVN_ID = "$Id$";

    public JonathanBootServlet() {
        super();
        if (LOGGER.isDebugEnabled()){
            LOGGER.debug(SVN_ID);
        }
    }

    public void init(ServletConfig config) throws ServletException {
        if (LOGGER.isDebugEnabled()){
            LOGGER.debug("in init()");
        }
        System.setProperty("tangosol.coherence.cacheconfig", "jonathan-tangosol-coherence.xml");
        super.init(config);
    }
}

Then add the following block in your web.xml:

    <servlet>
        <servlet-name>JonathanBootServlet</servlet-name>
        <servlet-class>lalou.jonathan.weblogic.technical.JonathanBootServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

Ensure this servlet is run before all others (1).