Question

I’m developing an application which requires two interfaces – one for mobile phones browsers and another one for normal PC browsers. The second interface needs to present more information and have a few more functions. of course, both of them are in the same project and use the same beans, etc. It os just the presentation layer which changes. For the time being, I have just the interface for mobile phones. It is accessible when I choose the address: //ip-address:8080/App/ but not when I try to go directly to the page with that interface: //ip-address:8080/App/page.jsp. I got the following error:

org.apache.jasper.JasperException: An
exception occurred processing JSP page
/page.jsp at line 30

javax.faces.context.FacesContext
context =
javax.faces.context.FacesContext.getCurrentInstance();
30:
context.getViewRoot().setLocale(newLocale);
31: %> 32: 33:

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

root cause

java.lang.NullPointerException
org.apache.jsp.page_jsp._jspService(page_jsp.java:91)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

Of course I have the information in my web.xml that the welcome page is set to

<welcome-file-list>
    <welcome-file>faces/page.jsp</welcome-file>
</welcome-file-list>

if I were to remove this part from the web.xml would I be able to reach that page or is the problem related to something else? In the end I would like to reach different interfaces by providing links like this:

//ip-address:8080/App/mobile_page.jsp
//ip-address:8080/App/browser_page.jsp

Thanks for any input.
Best Regards,
sass.

Answer 1

This exception is telling that the FacesContext#getCurrentInstance() is returning null. This means that the FacesContext is not been created. The one who is responsible for that is the FacesServlet. This in turn means that the FacesServlet is not been invoked at all.

To invoke the FacesServlet you need to ensure that the request URL matches the url-pattern of the FacesServlet as definied in the web.xml.

You seem to have mapped the FacesServlet on /faces/*. So, you need to open the page by http://ip-address:8080/App/faces/page.jsp and thus not by http://ip-address:8080/App/page.jsp.