Recipe 14.5. Java Extension Function Using the Package Format Namespace

<xsl:stylesheet 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xalan="http://xml.apache.org/xslt"
xmlns:myJava="xalan://java.lang">
   
<xalan:component prefix="Math" functions="sin cos tan atan">
 <xalan:script lang="javaclass" src="java.lang"/>
</xalan:component>
   
<xsl:variable name="pi" select="4.0 * myJava:Math.atan(1.0)"/>
   
<!-- ... -->
   
</xsl:stylesheet>

This form is useful if you want to reference many classes within the same package.