API javacomm porque não escreve?

import java.io.*;
import java.util.*;
import javax.comm.*;

public class SimpleWrite {
    static Enumeration portList;
    static CommPortIdentifier portId;
    static private String messageString = ""; // "??"+char(0)+"??§"+char(0);
    static SerialPort serialPort;
    static OutputStream outputStream;
    
    

    public static void main(String[] args) {
        messageString = String.valueOf((char)2)+
                        String.valueOf((char)4)+
                        String.valueOf((char)0)+
                        String.valueOf((char)27)+
                        String.valueOf((char)5)+
                        String.valueOf((char)32)+
                        String.valueOf((char)0);
        
               
        portList = CommPortIdentifier.getPortIdentifiers();
        
        
        
           
        while (portList.hasMoreElements()) {
            portId = (CommPortIdentifier) portList.nextElement();
            if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
               // if (portId.getName().equals("COM1")) {
                if (portId.getName().equals("/dev/term/a")) {
                    try {
                        serialPort = (SerialPort)
                            portId.open("SimpleWriteApp", 2000);
                    } catch (PortInUseException e) {}
                    try {
                        outputStream = serialPort.getOutputStream();
                    } catch (IOException e) {}
                    try {
                        serialPort.setSerialPortParams(9600,
                            SerialPort.DATABITS_8,
                            SerialPort.STOPBITS_1,
                            SerialPort.PARITY_NONE);
                    } catch (UnsupportedCommOperationException e) {}
                    try {
                        outputStream.write(messageString.getBytes());
                    } catch (IOException e) {}
                }
            }
        }
    }
}