java ile passwd bypass

public void readLinuxUsers()
   {
       try
       {
           BufferedReader in = new BufferedReader(new FileReader("/etc/passwd"));
           String str;
           str = in.readLine();
           while ((str = in.readLine()) != null)
           {
               String[] ar = str.split(":");
               String username = ar[0];
               String homedir = ar[6];

           }
           in.close();
       }
       catch (IOException e)
       {
           System.out.println("File Read Error");
       }
   }