android - Is it possible to run multiple AsyncTask in same time?

Question

I've two activities in my application. In my Activity A I'm using one AsyncTask and second Activity B also using another one AsyncTask. In my Activity A I've upload some data to server and in my Activity B I'm trying to download some other data from server. Both these are running in AsyncTask. My problem is when I trying to download data from server in Activity B onPreExecute() method was called but doInBackground() method was not called it is waiting up to the first Activity A's doInBackground() action finished. Why it is happened? Is it possible to run more than one background actions at a same time..

In Activity A

ImageButton submit_button = (ImageButton) findViewById(R.id.submit_button);

submit_button.setOnClickListener(new OnClickListener() 
    {
        public void onClick(View record_button) 
        {
                       new Save_data().execute();
        }
       });
class Save_data extends AsyncTask<String, Integer, Integer> 
 {
    protected void onPreExecute() 
    {

}
    protected Integer doInBackground(String... arg0) 
{
     //uploading data here
    }

 }

In my Activity B

ImageButton get_button = (ImageButton) findViewById(R.id.get_button);
    get_button.setOnClickListener(new OnClickListener() 
        {
            public void onClick(View record_button) 
            {
                           new download_process().execute();
            }
           });
    class download_process extends AsyncTask<String, integer, integer>
     {
        protected void onPreExecute() 
        {
       Log.e("pre-execute","has been called");//This Log works well
    }
         protected Integer doInBackground(String... arg0) 
    {
         //downloading data here
        }   
     }

Answer 1

use executor as follows

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
    new Save_data().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, location);
} else {
    new Save_data().execute(location);
}

See this