xsl:if test for null string giving TransformerException

[Robert Kattke]

I'm getting a TransformerException when running Tomcat and calling a
Servlet that use XML to create DOM and XSL to create webpage.

I'm posting just the snippet of XSL code and the Error here. Full
listing should be in my next thread. Funny thing is from a command
line I can run Process without an error. Why would Tomcat hiccup and
belch ?
Maybe I should be investigating my JARs in the classpath ?
*** note error occurring in ln 65 ***

<xsl:choose>
65 <xsl:when test="site = ''">
<xsl:text>N/A</xsl:text>
</xsl:when>
<xsl:otherwise>
<a>
<xsl:attribute name="href">
<xsl:value-of select="site"/>
</xsl:attribute>Website
</a>
</xsl:otherwise>

</xsl:choose>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
; SystemID: ; Line#: 65; Column#: 34
javax.xml.transform.TransformerException: Unknown error in XPath
at org.apache.xpath.XPath.bool(XPath.java:411)
at org.apache.xalan.templates.ElemChoose.execute(Elem Choose.java:162)
at org.apache.xalan.transformer.TransformerImpl.execu teChildTemplates(TransformerImpl.java:2182)at
.... xalan.templates.ElemLiteralResult.execute(ElemLite ralResult.java:678)
...

....
....
....

at org.apache.xpath.objects.XNodeSet.compare(XNodeSet .java:619)
at org.apache.xpath.objects.XNodeSet.equals(XNodeSet. java:706)
at org.apache.xpath.operations.Equals.operate(Equals. java:82)
at org.apache.xpath.operations.Operation.execute(Oper ation.java:146)
at org.apache.xpath.Expression.bool(Expression.java:2 08)
at org.apache.xpath.XPath.bool(XPath.java:388)
... 66 more
---------
java.lang.NullPointerException

Maybe there is a better way to check for blank or null string.
TIA for you suggestions and references.

[Robert Kattke]

> I'm getting a TransformerException when running Tomcat and calling a

Servlet that use XML to create DOM and XSL to create webpage.
65 <xsl:when test="site = ''"> Error on this line

Also tried this variation
<xsl:when test="string-length(site) > 0">

still getting:
; SystemID: ; Line#: 65; Column#: 48
javax.xml.transform.TransformerException: Unknown error in XPath

Help - something must not be configured right on my system.

[Robert Kattke]

<xsl:when test="string-length(site) > 0"> Error here

Help - something must not be configured right on my system.

How would I check what actual jar's are being used by Tomcat 4.0.4 on
WXP ?
I'm assumming check my master environment variables and then analyze
the batch files ( possibly using echo to see the classpath ).