How to avoid WSOD (blank screen) while loading long-running initialization data in Struts2?

Question

I need to do the following:

1. User logs in.
2. Redirected to welcome screen.
3. Looks at the welcome screen while lots of records are loaded.

Answer 1

The right way is the one already suggested by AleksandrM in comments: open the page, show an indicator while you call an ajax action (let's say with jQuery, for convenience), then render the result and remove the indicator. It's easier than you think:

public class MainAction extends ActionSupport {    
    public String execute() {
        return SUCCESS;
    }
}

public class AjaxAction extends ActionSupport {    
    @Autowired
    private ServiceDelegate myService;

    private Stuff myStuff; // with getter

    public String execute() {
        myStuff = myService.loadLongStuff();
        return SUCCESS;
    }
}

Your AJAX action can either return JSON data, a JSP snippet or a Stream of binary data. Choose the way you prefer. For example, if you map SUCCESS of AjaxAction to a JSP snippet, your JSP snippet will be:

ajaxSnippet.jsp

<%@ taglib prefix="s" uri="/WEB-INF/struts-tags.tld" %>
Stuff: 

Then in your main.jsp, show the indicator in the div you will overwrite with the AJAX call's result:

main.jsp