java.util.Iterator java.util.List.iterator()

Question

Android 7.0报错，其他 暂时没有报错，报错大概原因是
Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator() on a null object reference

try {    
        HttpAsyncTask task = new HttpAsyncTask();
        HttpPost post = new HttpPost(url + "?" + params);
        FLog.e(PostTAG, url + "?" + params.toString());
        List list = new ArrayList();
        list.add(post);
        list.add(handler);
        list.add(decoder);
        Log.d("haoxingling_http","是否执行");
        if (android.os.Build.VERSION.SDK_INT > 10) {
            task.executeOnExecutor(Executors.newCachedThreadPool(), list);
        }else{
            task.execute(list);
        }
    } catch (Exception ex) {
        dismissProgressDialog();
        if (handler != null) {// 比如logout,可能是空
            handler.getIExceptionHandler().processException(ex);
        }
    }