Валидатор

FileWriter writeFile = new FileWriter(fileName2,true);

 ****
 ****

writeFile.close();

public static void main(String[] args) throws IOException {
        String fileName1 = args[0];
        String fileName2 = args[1];

        BufferedReader readerFile1 = new BufferedReader(new FileReader(fileName1));

        String s,check="";
        while ((s = readerFile1.readLine()) != null){
            check = check+s;
        }

        readerFile1.close();

        String answer[] = check.split(" ");

        BufferedWriter writeFile = new BufferedWriter( new FileWriter(fileName2,true));

        int i = 0;
        for (; i < answer.length; i++) {
            if(answer[i].length()>6) {
                writeFile.write(answer[i]);
                break;
            }
        }

        for (; i < answer.length; i++) {
            if(answer[i].length()>6) {
                writeFile.write(","+answer[i]);
            }
        }

        writeFile.close();
    }