What trigger to update org.eclipse.wst.server.core

Question

I have problems using relative routes in an onClick in a .java of a button in a .zul. Im using Apache and eclipse.

The problem is that when using the relative route it doesent complete with the project route, it completes with the Eclipse route while using apache.

Then I got this solution, using implements WebAppInit and implementing this metod:

//principalPath is declared at the start of the class(String)
//Resources is inside webapp
@Override
    public void init(WebApp wapp) throws Exception {
        // TODO Auto-generated method stub
        principalPath = wapp.getRealPath("/Resources/");
}

This worked fine but when I added another File in Resources it stoped working. I discovered that this metod gives me the path of a temporal folder that copies my project webapp inside: eclipse-workplace2.metadata.plugins\org.eclipse.wst.server.core\tmp2\wtpwebapps\myProject

My doubt is what triggers eclipse to refresh that copy of the temporal webapp?