Xalan Java variable not assigned to Java object

[Richard R. McKinley]

I am defining a varible through the following method so that I keep the 
dependability of functional programming.  Notice how I start by cloning 
an object and I never modify that object which is assigned to a 
variable.  I don't want side effects:
<xsl:variable name="selected-month">
   <xsl:variable name="selected-month" select="java:clone($calendar)"/>
   <xsl:if test="java:set($selected-month, $date-field-value, 1)"/>
   <xsl:if test="java:add($selected-month, $month-field-value, 
$month-offset)"/>
   <xsl:value-of select="$selected-month"/>
</xsl:variable>

So, while I manipulate the value of the internal variable, it is only 
used to temporarily define the final outcome.  However, <xsl:value-of> 
is not doing the same thing that <xsl:variable select=""/> would do.  My 
variable is not getting a Java object assigned.  When I later try to 
reference it for example:
<xsl:value-of select="java:get($selected-month, $month-field-value)"/>

I get this error:  org.apache.cocoon.ProcessingException: Failed to 
execute pipeline.: java.lang.RuntimeException: 
java.lang.NoSuchMethodException: For extension function, could not find 
method org.apache.xml.dtm.ref.DTMNodeIterator.get([ExpressionContext,] 
#NUMBER).

Any thoughts?  Thanks,
RRM