UI manager Look and Feel sama dengan sistem operasi

       try {
         UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
     } catch (Exception ex) {
         ex.printStackTrace();
     }

Properties Factory buat nyimpen setingan file

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Reader;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

public class PropertyFactory {

   public static void save(Properties p, String fileName, String comment) {
       PrintWriter pw = null;
       try {
           pw = new PrintWriter(fileName);
       } catch (FileNotFoundException ex) {
           Logger.getLogger(PropertyFactory.class.getName()).log(Level.SEVERE, null, ex);
       }
       try {
           p.store(pw, comment);
       } catch (IOException ex) {
           Logger.getLogger(PropertyFactory.class.getName()).log(Level.SEVERE, null, ex);
       }
   }

   public static Properties read(String fileName) {
       Properties p = new Properties();
       Reader r = null;
       try {
           r = new FileReader(fileName);
       } catch (FileNotFoundException ex) {
           Logger.getLogger(PropertyFactory.class.getName()).log(Level.SEVERE, null, ex);
       }
       try {
           p.load(r);
       } catch (IOException ex) {
           Logger.getLogger(PropertyFactory.class.getName()).log(Level.SEVERE, null, ex);
       }
       return p;
   }
}

List available port in java

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

public class ListPorts {

   public static void main(String args[]) {
       Enumeration ports = CommPortIdentifier.getPortIdentifiers();
       while (ports.hasMoreElements()) {
           CommPortIdentifier port = (CommPortIdentifier) ports.nextElement();
           String type;
           switch (port.getPortType()) {
               case CommPortIdentifier.PORT_PARALLEL:
                   type = "Parallel";
                   break;
               case CommPortIdentifier.PORT_SERIAL:
                   type = "Serial";
                   break;
               default:
                    type = "Unknown";
                   break;
           }
           System.out.println(port.getName() + ": " + type);
       }
   }
}