public class BillyApplication extends Application {
    private static int DISK_IMAGECACHE_SIZE = 1024*1024*10;
    private static Bitmap.CompressFormat DISK_IMAGECACHE_COMPRESS_FORMAT = Bitmap.CompressFormat.PNG;
    private static int DISK_IMAGECACHE_QUALITY = 100;  //PNG is lossless so quality is ignored but must be provided
    RequestQueue req;
    @Override
    public void onCreate() {
        super.onCreate();
        init();
    }

    private void init() {
        Log.d(getClass().getName(), "This is init");
       req = Volley.newRequestQueue(this);
       createImageCache();
    }

    private void createImageCache() {
        ImageCacheManager.getInstance().init(this,
                this.getPackageCodePath()
                , DISK_IMAGECACHE_SIZE
                , DISK_IMAGECACHE_COMPRESS_FORMAT
                , DISK_IMAGECACHE_QUALITY
                , ImageCacheManager.CacheType.MEMORY);
    }

    public RequestQueue getRequestQueue(){
        if(req == null) {
            Log.d(getClass().getName(), "Request Queue object is not initialized");
            req = Volley.newRequestQueue(this);
        }
        return req;
    }
}