New to Java

i'm writting a java program to use xslt to transform the xml file. i'm encountering the problem when i try to convert the xslt file into string. i've defined my utility class called 'XmlUtil' to carry out the operation of transform xml file through xslt. but in my main java program i need to convert both xml and xslt file into a string in order to input them in my function argument. my function argument is as follows:
String htmlString = XmlUtil.applyXsltString(xmlContent, xsltString);

i've already converted xmlcontent into string by using:
xmlContent = xmlContentBuffer.toString();

but i don't know how to convert 'xsltString' now ? i've searched the google for an hour but i cannot find the solution. anyone can help ?

detail of my souce code is as follow:
import java.io.*;
import java.net.*;
import java.lang.*;
import java.io.StringReader;
import java.lang.reflect.Array;
import java.util.Properties;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamSource;

import org.apache.xml.serializer.OutputPropertiesFactory;
import org.apache.xml.serializer.Serializer;
import org.apache.xml.serializer.SerializerFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

import XmlUtil;

public class FileDownload {
public static void download(String address, String localFileName){
OutputStream out = null;
URLConnection conn = null;
InputStream in = null;
StringBuffer xmlContentBuffer = new StringBuffer();
String temp = new String();
String xmlContent;
try {
URL url = new URL(address);
out = new BufferedOutputStream(
new FileOutputStream(localFileName));
conn = url.openConnection();
in = conn.getInputStream();
byte[] buffer = new byte[1024];
int numRead;
long numWritten = 0;
System.out.println (in.toString ());
while ((numRead = in.read(buffer)) != -1) {
out.write(buffer, 0, numRead);
numWritten += numRead;
temp = new String(buffer);
xmlContentBuffer.append(temp);
}
System.out.println(localFileName + "\t" + numWritten);
xmlContent = xmlContentBuffer.toString();

String htmlString = XmlUtil.applyXsltString(xmlContent, xsltString);
} catch (Exception exception) {
exception.printStackTrace();
} finally {
try {
if (in != null) {
in.close();
}
if (out != null) {
out.close();
}
} catch (IOException ioe) {
}
}
}
public static void download(String address) {
int lastSlashIndex = address.lastIndexOf('/');
if (lastSlashIndex >= 0 &&
lastSlashIndex < address.length() - 1) {
download(address, address.substring(lastSlashIndex + 1));
} else {
System.err.println("Could not figure out local file name for " + address);
}
}
public static void main(String[] args) {
for (int i = 0; i < args.length; i++) {
download(args);
}
}

}