Question

I’m trying to use a custom taglib in a portlet application.

The portlet uses Spring MVC Portlet, but I don’t think that’s relevant here.

The tag extends TagSupport. It tries to get the HttpSession using pageContext.getSession(), but it returns null resulting in a NullPointerException in the later code.

public class keyboard extends TagSupport {

    public int doStartTag() {
        ...
        HttpSession session = pageContext.getSession();
        ...
        session.setAttribute("sesKeyboad", keyboard); // <-- NullPointerException
    }
}

I’m not supposed to modify the taglib, it already worked in another portlet.
Any idea why the HttpSession is not initialized in the pageContext ?

Answer 1

It’s possible that the JSP containing the associated tag is using the page directive and setting its session attribute to false.