当我使用 NetBeans 6.8 和 Eclipse 运行此代码时，为什么输出会有所不同?

When I am running the following code using Eclipse and NetBeans 6.8. I want to see the available COM ports on my computer. When running in Eclipse it is returning me all available COM ports but when running it in NetBeans, it does not seem to find any ports ..

public static void test(){
    Enumeration lists=CommPortIdentifier.getPortIdentifiers();

    System.out.println(lists.hasMoreElements());
    while (lists.hasMoreElements()) {
        CommPortIdentifier cn=(CommPortIdentifier)lists.nextElement();

        if ((CommPortIdentifier.PORT_SERIAL==cn.getPortType())) {
            System.out.println(
              "Name is serail portzzzz " +
              cn.getName() +
              " Owned status " +
              cn.isCurrentlyOwned());

            try{
                SerialPort port1=(SerialPort)cn.open("ComControl",800000);
                port1.setSerialPortParams(
                  9600,
                  SerialPort.DATABITS_8,
                  SerialPort.STOPBITS_1,
                  SerialPort.PARITY_NONE);
                System.out.println("Before get stream");
                OutputStream out=port1.getOutputStream();
                InputStream input=port1.getInputStream();
                System.out.println("Before write");
                out.write("AT".getBytes());
                System.out.println("After write");
                int sample=0;
                //while((( sample=input.read())!=-1)){
                System.out.println("Before read");
                //System.out.println(input.read() + "TEsting ");
                //}
                System.out.println("After read");
                System.out.println("Receive timeout is "+port1.getReceiveTimeout());
            }
            catch(Exception e) {
                System.err.println(e.getMessage());
            }
        }
        else {
            System.out.println(
              "Name is parallel portzzzz " +
              cn.getName() +
              " Owned status " +
              cn.isCurrentlyOwned() +
              cn.getPortType()+"    ");
        }
    }
}

使用 Netbeans 输出，

true
Name is serail portzzzz COM1 Owned status false
Before get stream
Before write
After write
Before read
After read
Receive timeout is -1
Name is serail portzzzz COM2 Owned status false
Before get stream
Before write
After write
Before read
After read
Receive timeout is -1
Name is parallel portzzzz LPT1 Owned status false2
Name is parallel portzzzz LPT2 Owned status false2