I have the following for random number generator. But it is not working. 

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:java="http://xml.apache.org/xalan/java">
	<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
	<xsl:template match="/">
	<xsl:text>aa</xsl:text>
	<xsl:variable name="rnd">
	<xsl:value-of select="java:java.lang.Math.random()" xmlns:java="http://xml.apache.org/xalan/java"/>
	</xsl:variable>
	<xsl:value-of select="$rnd"/>
	</xsl:template>
</xsl:stylesheet>

I am receiving the following error message: 
Error in XPath expression
Unknown function - Name and number of arguments do not match any function signature in the static context - 'http://xml.apache.org/xalan/java:java.lang.Math.random'