Problem solved, it was a use case whereby the doStartTag() method
returned a SKIP_BODY instead of a EVAL_BODY_INCLUDE

Regards,
Peter Dolukhanov

-----Original Message-----
From: A mailing list about Java Server Pages specification and reference
[mailto:[EMAIL PROTECTED] On Behalf Of Peter Dolukhanov
Sent: 17 March 2003 13:36
To: [EMAIL PROTECTED]
Subject: TagLib Problem

Dear All,



I have encountered a small problem whilst using Tag Libraries. I have
two relatively simple tags "loggedIn" and "notLoggedIn". The purpose, is
to check whether a user is logged in or not, and display whatever is
within the tag accordingly.



However, I am encountering this exception:



java.lang.NullPointerException
        at
javax.servlet.jsp.tagext.BodyTagSupport.getPreviousOut(BodyTagSupport.ja
va:190)
        at
com.rd_uk.taglibrary.LoggedInTag.doEndTag(LoggedInTag.java:68)



The code in question is:



public int doEndTag() throws JspTagException

    {

        if (userName != null)

        {

            try

            {

                BodyContent body = getBodyContent();

                body.writeOut(getPreviousOut());

                body.clearBody();

            }

            catch (IOException e)

            {

                throw new JspTagException(e.toString());

            }

        }

        return EVAL_PAGE;

    }



I have read on several mailing lists, that this problem arises if
BodyContent is null. So, to remedy this, I have added a line which only
performs the getPreviousOut and clearBody operations if body != null.
However, in this instance body is obviously null, so nothing within the
tags is displayed.



What could be a reason for this, as this is critical to this tag
library?



Best regards,

Peter Dolukhanov

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