wlan.dll is not giving out put in windows7

public class Wlan {
    private static native int WiFi_Create();
    private static native int WiFi_GetUsedAPI();
    private static native int WiFi_CreateAPList();
//    private static native int WiFi_getAPListSize();
    private static native String WiFi_GetAPName(int ind);
    private static native byte[] WiFi_GetAPMAC(int ind);
    private static native int WiFi_GetAPRSSI(int ind);
    private static native int WiFi_InfrastructureMode(int ind);
    private static native void WiFi_Destroy();

    private static int adapterListSize, apListSize;

    static {
        /*
        try {
            Runtime.getRuntime().exec("net stop \"Wireless Zero Configuration\""); //stops the WZC
        }
        catch(Exception ex) {}
        try {
            Thread.sleep(1000);
        }
        catch (Exception ex) {}
        */
        System.load("C:/Users/admin/Desktop/10-4-2011/WlanDLL/WlanDLL/Wlan.dll");
        //System.loadLibrary("Wlan.dll"); //loads the library
        adapterListSize = -1;
        apListSize = 0;
    }

    //calls function to create the wlanapi object, the list of Wi-Fi adapters, and returns its size
    public static int createAdapterList() {
        if (adapterListSize < 0)
            adapterListSize = WiFi_Create();
//        System.out.println(adapterListSize);
        return adapterListSize;
    }

    //returns textual information on the used interface and the number of Wi-Fi adapters
    public static String getInfo() {
        String str;
        switch (adapterListSize) {
            case -1: str = "Unable to find a valid method for retrieving a list of network interfaces."; break;
            case 0: str = "No WiFi interfaces found."; break;
            case 1: str = "WiFi interface found."; break;
            default: str = "Found " + Integer.toString(adapterListSize) + " WiFi interfaces.";
        }
        if (adapterListSize >= 0) {
            switch (WiFi_GetUsedAPI()) {
                case -1: adapterListSize = -1; break;
                case 0: str = "Using (K)NetworkManager over D-BUS. " + str; break;
                case 1: str = "Using Wireless Zero Configuration (WZC) service (not recommended on WinXP). " + str; break;
                case 2: str = "Using Native Wifi API (do not use on WinXP). " + str; break;
                case 3: str = "Using NDIS User-Mode I/O (NDISUIO) driver. " + str; break;
            }
        }
        return str;
    }

    //calls the function to generate/update AP list and returns its size
    public static int createAPList() {
        if (adapterListSize < 1) {
             System.out.println(adapterListSize);
            apListSize = 0;
            return -1;
        }
        apListSize = WiFi_CreateAPList();
         System.out.println("hi"+ apListSize);
        return apListSize;
    }

    //returns AP list size
    public static int getAPListSize() {
//        System.out.println("hi");
        return apListSize;
    }

    //returns name of a particular AP from the list
    public static String getAPName(int ind) {
        if ((adapterListSize < 1) || (ind >= apListSize))
            return "nnn";
        return WiFi_GetAPName(ind);
    }

    //returns mac address of a particular AP from the list
    public static byte[] getAPMAC(int ind) {
        if ((adapterListSize < 1) || (ind >= apListSize))
            return null;
        byte[] tmp = WiFi_GetAPMAC(ind);
        if (tmp.length < 6)
            System.out.println("Error getting MAC address.");
        return tmp;
    }

    //returns RSSI of a particular AP from the list
    public static int getAPRSSI(int ind) {
        if ((adapterListSize < 1) || (ind >= apListSize))
            return -2002;
        int tmp = WiFi_GetAPRSSI(ind); //expected values are around -10..-100
        if (tmp <= -1000)
            System.out.println("Error getting RSSI.");
        return tmp;
    }

    //returns type (InfrastructureMode) of a particular AP from the list
    //With NDISUIO and Native Wifi API: 0 = Independent (peer); 1 = Infrastructure (AP); 2 = AutoUnknown
    public static int getAPInfrastructureMode(int ind) {
        if ((adapterListSize < 1) || (ind >= apListSize))
            return -1;
        return WiFi_InfrastructureMode(ind);
    }

    //calls the function which destroys the wlanapi object
    public static void destroy() {
        WiFi_Destroy();
        adapterListSize = -1;
        apListSize = 0;
    }
}