Multiple DWR classes in web.xml (using annotations)

I want to use annotated DWR classes in my project. So I created 2 classes. Assume Dwr1.java and Dwr2.java

In my web.xml I have the following entry to load the classes:

<servlet>
    <display-name>DWR Servlet</display-name>
    <servlet-name>dwr-invoker</servlet-name>
    <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
    <init-param>
        <param-name>debug</param-name>
        <param-value>true</param-value>
    </init-param>
    <init-param>
        <param-name>activeReverseAjaxEnabled</param-name>
        <param-value>true</param-value>
    </init-param>
    <init-param>
        <param-name>classes</param-name>
        <param-value>
           de.package.Dwr1,
           de.another.package.Dwr2
       </param-value>
    </init-param>
    <load-on-startup>3</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>dwr-invoker</servlet-name>
    <url-pattern>/dwr/*</url-pattern>
</servlet-mapping>

The Proplem is that the Dwr2 Class does not get instantiated. If I remove Dwr1 from my web.xml, Dwr2 gets instantiated, but if I have both entries in my web.xml only Dwr1 gets instantiated.

Dwr1 is a very simple class:

@RemoteProxy
public class Dwr1 {

    @RemoteMethod
    public String getString(String key) {
        return Util.GetString(key);
    }
}

Dwr2 is a little bit more complex like:

@RemoteProxy
public class Dwr2 {
        
    @RemoteMethod
    public Dwr2() {
        ServerUtil.registerOnFE(new UpdateClient());
    }
    
    private void updateBrowser(final String arg) {
        Browser.withPage("/page.do", new Runnable() {
            @Override
            public void run() {
                ScriptSessions.addFunctionCall("update", arg);
           }
        });
    }
    
    private class UpdateClient {
        @Override
        onRecieveUpdate(String arg) {
            updateBrowser(arg);
        }
    }
}

Are there any Mistakes in my classes or in my web.xml? Or how can I instantiate multiple DWR Classes with Annotations?

Solution

I found a solution to fix this issue. It seems like DWR doesn´t instantiate every class on the server-startup. (But it apparently does if there is only one class defined in the config file). However, I just implemented a "dummy-method" in dwr-classes, called "start()". The Method does nothing, but when it get's called from javascript, the class gets instantiated. My solution looks like this:

<servlet>
    <display-name>DWR Servlet</display-name>
    <servlet-name>dwr-invoker</servlet-name>
    <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
    <init-param>
        <param-name>debug</param-name>
        <param-value>true</param-value>
    </init-param>
    <init-param>
        <param-name>activeReverseAjaxEnabled</param-name>
        <param-value>true</param-value>
    </init-param>
    <init-param>
        <param-name>classes</param-name>
        <param-value>
           de.package.Dwr1,
           de.another.package.Dwr2
       </param-value>
    </init-param>
    <load-on-startup>3</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>dwr-invoker</servlet-name>
    <url-pattern>/dwr/*</url-pattern>
</servlet-mapping>

Dwr1

@RemoteProxy
public class Dwr1 {

    @RemoteMethod
    public String getString(String key) {
        return Util.GetString(key);
    }
}

Dwr2

@RemoteProxy 
public class Dwr2 {

    public Dwr2() {
        ServerUtil.registerOnFE(new UpdateClient());
    }

    @RemoteMethod
    public void start() {
         //Do nothing
    }

    private void updateBrowser(final String arg) {
        Browser.withPage("/page.do", new Runnable() {
            @Override
            public void run() {
                ScriptSessions.addFunctionCall("update", arg);
           }
        });
    }

    private class UpdateClient {
        @Override
        onRecieveUpdate(String arg) {
            updateBrowser(arg);
        }
    } 
}

A call of the start()-method of Dwr2 class triggers the insantiation of it.