why does ByteArrayInputStream doesn't return expected results?

I am trying to interact with an application in windows server through telnet, so I am using TelnetClient() method. I could interact (send commands and retrieve results) using System.in.read(), however I want this program to run automatically without using any keyboard inputs. So, my question is, why does System.in.read() works, yet ByteArrayInputStream doesn't?

This is my code so far :

public class telnetExample2 implements Runnable, TelnetNotificationHandler{
 static TelnetClient tc = null;
 public static void main (String args[]) throws IOException, InterruptedException{
  tc = new TelnetClient();
   while (true){
    try{
     tc.connect("192.168.1.13", 8999);
     }
     catch (SocketException ex){
      Logger.getLogger(telnetExample2.class.getName()).log(Level.SEVERE, null,ex);
     }
    Thread reader = new Thread(new telnetExample2());
    tc.registerNotifHandler(new telnetExample2());
    String command = "getversion"; //this is the command i would like to write
    OutputStream os = tc.getOutputStream();
    InputStream is = new ByteArrayIn开发者_如何学PythonputStream(command.getBytes("UTF-8")); //i'm using UTF-8 charset encoding here
    byte[] buff = new byte[1024];
    int ret_read = 0;
    do{
     ret_read = is.read(buff);
     os.write(buff, 0, 10)
     os.flush();
    while(ret_read>=0);
    }
 }

public void run(){
 InputStream instr = tc.getInputStream();
 try{
  byte[] buff = new byte[1024];
  int ret_read = 0;
   do{
    ret_read = instr.read(buff);
    if(ret_read >0){
     System.out.print(new String(nuff, 0, ret_read));
    }
   while(ret_read>=0);}
  catch(Exception e){
  System.err.println("Exception while reading socket:" + e.getMessage());
  }
 }

public void receiveNegotiation(int i, int ii){
 throw new UnsupportedOperationException("Not supported");
 }
}

---

InputStream is = new ByteArrayInputStream(command.getBytes("UTF-8")); //i'm using UTF-8 charset encoding here
byte[] buff = new byte[1024];
int ret_read = 0;
do{
 ret_read = is.read(buff);
 os.write(buff, 0, 10)
 os.flush();
while(ret_read>=0);
}

You can reduce those 9 lines that don't work to os.write(command.getBytes("UTF-8")); which does.

Why you thought that reading up to 1024 bytes into a buffer and then writing out only the first ten of them was ever going to work is a mystery.