How to update the record in a File (without closing Writer)?

Question

Well i've got one issue:
I want my program to record in a file updating any time i.e the records are added in append.
But i want the record must be done in a file even if the Writer is not closed because I'd like to see the all logs of user and the main thing is sometimes there could be issue of software crash, powercut off or any So for that reason i 've made code like this but it doesn't update but it only override:
public boolean write(String s){
        boolean isFinished = false;
        try{
            FileOutputStream out = new FileOutputStream("C:\\new.txt"); 
            int i = 0;              
            while(i != s.length()){
                out.write(s.charAt(i));
                i++;
            //here i've not closed file output stream
            isFinished = true;
        catch(IOException i){
            i.printStackTrace();
            isFinished = false;
        return isFinished;
    }

Answer 1

Well, Thanks for the help but,. i didn't understand
try not opening the file every time. As I only know that I need to open a file if i would like to update the records..
The update is not happening :
Firstly it shows like this (new.txt):
STOPSecondly it must show like this (new.txt) BUT NOT HAPPENING AS I EXPECTED:
STOPSTOPBut it's not hapenning