static String[] GpioChannels =                               
    { "0", "1", "4", "17", "21", "22", "10", "9" };

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        FileWriter[] commandChannels;
        
        try {
            
            /*** Init GPIO port for output ***/
            
            // Open file handles to GPIO port unexport and export controls
            FileWriter unexportFile = 
                    new FileWriter("/sys/class/gpio/unexport");
            FileWriter exportFile = 
                    new FileWriter("/sys/class/gpio/export");

            for (String gpioChannel : GpioChannels) {
                System.out.println(gpioChannel);
    
                // Reset the port
                unexportFile.write(gpioChannel);
                unexportFile.flush();
            
                // Set the port for use
                exportFile.write(gpioChannel);   
                exportFile.flush();

                // Open file handle to port input/output control
                FileWriter directionFile =
                    new FileWriter("/sys/class/gpio/gpio" + gpioChannel + 
                        "/direction");
            
                // Set port for output
                directionFile.write(GPIO_OUT);
                directionFile.flush();
            }

            /*** Send commands to GPIO port ***/
            
            commandChannels = new FileWriter[GpioChannels.length];
            
            for (int channum=0; channum < GpioChannels.length; channum++) {
                
                // Open file handle to issue commands to GPIO port
                commandChannels[channum] = 
                        new FileWriter("/sys/class/gpio/gpio" +
                        GpioChannels[channum] + "/value");
            }
            
            // Loop forever
            while (true) {
                
                for (int channum=0; channum < GpioChannels.length; channum++) {
                    // Set GPIO port ON
                    commandChannels[channum].write(GPIO_ON);
                    commandChannels[channum].flush();
                }
                
                // Wait for a while
                java.lang.Thread.sleep(200);
        
                // Set GPIO port OFF
                for (int channum=0; channum < GpioChannels.length; channum++) {
                    // Set GPIO port ON
                    commandChannels[channum].write(GPIO_OFF);
                    commandChannels[channum].flush();
                }
                
                // Wait for a while
                java.lang.Thread.sleep(200);
            }

        } catch (Exception exception) {
            exception.printStackTrace();
        }