Problemas com envio de socket

private OutputStream fromClientSocket;

private void ACK() throws IOException{
		try {
			
			
			String ack = "5356000D0000002BF400060000";
			
			fromClientSocket.write( this.stringToByte(ack) );  
			fromClientSocket.flush();
			
		} catch (Exception ex) {
			Logger.getLogger(TCPClient.class.getName()).log(Level.SEVERE, null, ex);
		}
	}

private byte[] stringToByte(String str ){
		byte[] stringCompleta = new byte[str.length() / 2];
		int j = 0;
		for (int i = 0; i < str.length(); i += 2)
		{
			stringCompleta[j] = (byte) Integer.parseInt(str.substring(i, i + 2), 16);
			j++;
		}
		return stringCompleta;
	}

public void run(){
			
			BufferedReader in;

			try {
				
				in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
				
				System.out.println ("Waiting...");
								
				while( clientSocket.isConnected() ){
					
					char[] cbuf = new char[224];
					in.read(cbuf);
					String texto = getStringFromUnicode( cbuf );
					System.out.println( texto );
					cbuf = null;
					
				}
 
				System.err.println("Fechando Comunicação com o Rastreador...");
				in.close(); 
				clientSocket.close();
				
			} catch (IOException e) { 
				System.err.println("Conexão Fechada com o Rastredor..");
			} catch (Exception ex) {
				Logger.getLogger(TCPClient.class.getName()).log(Level.SEVERE, null, ex);
			}
			
		}

protected String getStringFromUnicode(char[] codes) throws IOException
	{
		if (codes == null) {
			return null;
		}
		 final StringBuilder hex = new StringBuilder(2 * codes.length);
		 for (final byte b : codes) {
			final int hiVal = (b & 0xF0) >> 4;
			final int loVal = b & 0x0F;
			hex.append((char) ('0' + (hiVal + (hiVal / 10 * 7))));
			hex.append((char) ('0' + (loVal + (loVal / 10 * 7))));
		 }
		 return hex.toString();
	}