[Java] Overwriting a line in a plain textfile with FileWriter

Hi,

Is it possible to find a line in a text file, and then overwrite that line with something else, or delete it altogether ? Here's some code

// set up file readers and writers
FileReader fRead = new FileReader("list.dat");
FileWriter fWrite = new FileWriter("list.dat",
                                    true);

BufferedReader bIn = new BufferedReader(fRead);
BufferedWriter bOut = new BufferedWriter(fWrite);

String line, currentName;

// userName is from a html form
try {
while((line = bIn.readLine()) != null) {
 StringTokenizer st = new StringTokenizer(line);
 currentName = st.nextToken();
 if(currentName.compareTo(userName) == 0) {
  bOut.write(userName + "Expired");
  break;
 }
 currentName = st.nextToken() // ignore next tkn
}

catch(IOException e) {}

Am I way off base here, or what? Any help is appreciated. thanks

Alex