Problem copying a File to another File

Question

My routine to take one File's content and overwrite another File doesn't seem to work with xml. Could anyone explain this behavior?
     * replaces one file's content with another
     * @param sourceFile
     * @param file_to_overwrite
     * @throws java.io.FileNotFoundException
     * @throws java.io.IOException
    public static void overwriteFile(File sourceFile, File file_to_overwrite) throws FileNotFoundException, IOException {
        BufferedReader br = new BufferedReader(new FileReader(sourceFile));
        BufferedWriter bw = new BufferedWriter(new FileWriter(file_to_overwrite));
        // overwrite destination file w/ source file
        String currentLine = new String();
        while ((currentLine = br.readLine()) != null) {
            bw.write(currentLine);
        br.close();
        bw.close();
    }when the overwritten file is opened in firefox I get this error
XML Parsing Error: no element foundwhen I open up the two documents in notepad to visually inspect, I see some square shaped characters in the original,
but not in the overwritten file.
opening the documents in wordpad shows the overwritten file to be all on one line whereas the original shows the nested form of the xml document.
Any thoughts or insight?

Answer 1

thank you both for your replies
FileInputStream fis = new FileInputStream(sourceFile);
FileOutputStream fos = new FileOutputStream(file_to_overwrite);
int ch;
while ((ch = fis.read()) != -1) {
    fos.write(ch);
fis.close();
fos.close();this seems to be working perfectly except it cuts off the final tag, <\log>
if i invoke another fos.write after the loop it inputs the value of -1 which is a "y"
what's happening at the end of the loop here?
<?xml version="1.0" encoding="windows-1252" standalone="no"?>
<!DOCTYPE log SYSTEM "logger.dtd">
<log>
  <record>
    <message>
    <\message>
  </record>
<\log>   <-------  goes missing on overwritten file