problem in interface between nfc reader and web application

[ahmed mego]

this code make interface between nfc reader and my web application any way i have value of nfc card (id) in the void method and i want to get it again i know that void return null but there are not any solutions for that . I tried to declare id as global variable but i have null

/*
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 * and open the template in the editor.
 */
package pkginterface;
/**
 *
 * @author ahmad
 */
import java.io.InputStream;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier; 
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent; 
import gnu.io.SerialPortEventListener; 
import java.util.Enumeration;

public class  serialtest implements SerialPortEventListener {
    SerialPort serialPort;
        /** The port we're normally going to use. */
	private static final String PORT_NAMES[] = {
			"COM3","COM1","COM2","COM4","COM5","COM6","COM7","COM8","COM9","COM10","COM11","COM12","COM13","COM14","COM15","COM16","COM17","COM18","COM19","COM20","COM21","COM22","COM23","COM24","COM25","COM26", // Windows
			};
	/** Buffered input stream from the port */
	private InputStream input;
	/** The output stream to the port */
	private OutputStream output;
	/** Milliseconds to block while waiting for port open */
	private static final int TIME_OUT = 2000;
	/** Default bits per second for COM port. */
	private static final int DATA_RATE = 9600;
    /**
     *
     */
    public static String  id;
public static byte [] chunk ;


	public void initialize() {
		CommPortIdentifier portId = null;
		Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();

		// iterate through, looking for the port
		while (portEnum.hasMoreElements()) {
			CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
			for (String portName : PORT_NAMES) {
				if (currPortId.getName().equals(portName)) {
					portId = currPortId;
					break;
				}
			}
		}

		if (portId == null) {
			System.out.println("Could not find COM port.");
			return;
		}

		try {
			// open serial port, and use class name for the appName.
			serialPort = (SerialPort) portId.open(this.getClass().getName(),
					TIME_OUT);

			// set port parameters
			serialPort.setSerialPortParams(DATA_RATE,
					SerialPort.DATABITS_8,
					SerialPort.STOPBITS_1,
					SerialPort.PARITY_NONE);

			// open the streams
			input = serialPort.getInputStream();
			output = serialPort.getOutputStream();

			// add event listeners
			serialPort.addEventListener(this);
			serialPort.notifyOnDataAvailable(true);
		} catch (Exception e) {
			System.err.println(e.toString());
		}
	}

	/**
	 * This should be called when you stop using the port.
	 * This will prevent port locking on platforms like Linux.
	 */
	public synchronized void close() {
		if (serialPort != null) {
			serialPort.removeEventListener();
			serialPort.close();
		}
	}

	/**
	 * Handle an event on the serial port. Read the data and print it.
	 */
	public synchronized void  serialEvent(SerialPortEvent oEvent ) {
		if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
			try {
				int available = input.available();
				byte chunk[] = new byte[available];
				input.read(chunk, 0x0, available);
 id= new String(chunk);


				// Displayed results are codepage dependent
				
			} catch (Exception e) {
				System.err.println(e.toString());
			}
		}
                
		// Ignore all the other eventTypes, but you should consider the other ones.
        }
   
     public static void main(String[] args) {
        // TODO code application logic here
        serialtest test =new serialtest();
        test.initialize();
  
  System.out.println(serialtest.id);
       
    }    
        
        
}

i want to get the value of id again


my output : null

please help me and thank you in advanve

[Ulf Dittmer]

Out of curiosity: what good does it do to connect a web app to an NFC reader? What devices might be in the vicinity of a web server?

[ahmed mego]

i use aurdino uno this not important i want only know how i can get value of id from void method donot worry about all code i only need to get value of id there any solution for that