try{
BufferedReader in4 =new BufferedReader(new FileReader("xxxx.txt"));
PrintWriter out1 =new PrintWriter(new BufferedWriter(new FileWriter("xxx1.txt")));
int lineCount = 1;
while((s = in4.readLine()) != null)
out1.println(lineCount++ + ":" + s);
out1.close();
in4.close();
}
catch(EOFException ex){
System.out.println("End of stream");
}