appView.addJavascriptInterface() does not work on API 17

i am able to use java function from my phonegap java script function and android 2.2 but same code is not run on API 17. what should i have to do to call native java code on from java script in API 17.

i use this code in my java file

 objCustomNativeAccess = new CustomNativeAccess(this, appView);
            appView.addJavascriptInterface(objCustomNativeAccess,
                    "CustomNativeAccess");
    super.loadUrl("file:///android_asset/www/index.html");

my CustomNativeAccess class is

public class CustomNativeAccess {
        private WebView mAppView;
        private DroidGap mGap;

        /**
         * Constructor
         * 
         * @param gap
         * @param view
         */
        public CustomNativeAccess(DroidGap gap, WebView view) {
            mAppView = view;
            mGap = gap;
        }

        /**
         * Get the device phone number
         * 
         * @return
         */
        public JSONObject login(String email, String password) {
            JSONObject object = new JSONObject();
                    object.put("Login_Status", login_status);
            object.put("date", dateString);
            return object;
        }

and in my java script i use this line to call this login function

 var value = window.CustomNativeAccess.login(email,pass);

so using this i successfully call this on api 2.2 but when i run this code on api 17 it give me error

Uncaught TypeError: Object [object Object] has no method 'login' at file:///android_asset/www/index.html:81

how i can i use this on api 17