Объединение нескольких csv файлов в один и при этом в результате появляются символы [] как избежать этого?

` ArrayList list = new ArrayList<>(); //String headers = null; String header = "Длина;Дата;Время;MJD;Геометрический фактор;Переменная среда;Binary;"; list.add(header); //System.out.println(list); String line = " "; String line1 = " "; String line2 = " "; String line3 = " ";

    try
    {
        BufferedReader br = new BufferedReader(new FileReader( s));
        BufferedReader r1 = new BufferedReader(new FileReader( s1));
        BufferedReader r2 = new BufferedReader(new FileReader( s2));
        BufferedReader r3 = new BufferedReader(new FileReader( s3));
        //String s1 =null;
        //String s2 = null;

        br.readLine();
        while ((line = br.readLine()) != null)
        {             
             list.add(line);                             
        }
        
        br.close();
        
        
        r1.readLine();
        while((line1 = r1.readLine()) != null)
        {               
             list.add(line1);
             }
                      
        r1.close();
        
       
        r2.readLine();
     while((line2 = r2.readLine()) != null)
        {
            
             list.add(line2);               
        }
     r2.close();
     
             
     r3.readLine();
     while((line3 = r3.readLine()) != null)
        {  
            list.add(line3);                
                     
        }
    r3.close();
    
    }
    catch (IOException ex)
    {
    Logger.getLogger(Merg.class.getName()).log(Level.SEVERE, null, ex);
    
    }`  
`JFileChooser chooser4 = new JFileChooser("C:\\Users\\Андрей\\Desktop");
     FileNameExtensionFilter filter = new FileNameExtensionFilter(
    "CSV files", "csv");
     chooser4.setFileFilter(filter);
             int rV = chooser4.showSaveDialog(chooser4);
           if (rV == JFileChooser.APPROVE_OPTION) {                
           String filenames=chooser4.getSelectedFile().getPath();
          //Iterator<File> iterFiles;
          //iterFiles = list.iterator()
           
           try (FileWriter fw = new FileWriter(new File(filenames)); 
        BufferedWriter bw = new BufferedWriter(fw)) {
               for (Iterator<String> it = list.iterator(); it.hasNext(); ) {
                   
                   String [] f = it.next().split(" , ");
                 
                   bw.write(Arrays.toString(f));
                   //bw.write("\n");
                   bw.newLine();
                                      
               }
             
               bw.close();
               fw.close();
               
               form1.dispose();
           } catch (IOException ex) {
}`