when do I see this? XSLTProcessor processor XSLTProcessor processor

I have the following lines of code.

import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import org.xml.sax.SAXException;
import org.apache.xalan.*;

public class ReadXslt {

    public static void main (String[] args) throws MalformedURLException,
SAXException {

        XSLTProcessor processor = null;
        String xmlFileName = "test.xml";
         String xsltFileName = "Read-Cdata.xslt";

        String xmlSystemId = new
File(xmlFileName).toURL().toExternalForm( );
   String xsltSystemId = new
File(xsltFileName).toURL().toExternalForm( );

   processor= XSLTProcessorFactory.getProcessor();

    }//end of main

}//end class

What is causing this error

ReadXslt.java:13: cannot find symbol
symbol : class XSLTProcessor
location: class ReadXslt
                XSLTProcessor processor = null;
                ^
ReadXslt.java:20: cannot find symbol
symbol : variable XSLTProcessorFactory
location: class ReadXslt
                processor= XSLTProcessorFactory.getProcessor();