Can an Android AsyncTask doInBackground be synchronized to serialize the task execution?

Is it possible to make AsyncTask.doInBackground synchronized - or achieve the same result in another way?

class SynchronizedTask extends AsyncTask {

    @Override
    protected synchronized Integer doInBackground(Object... params) {
        // do something that needs to be completed 
        // before another doInBackground can be called
    }
}

In my case, any AsyncTask.execute() can be started before a previous one has completed, but I need to execute the code in doInBackground only after the previous task has finished.

EDIT: As correctly pointed out, the synchronization works only on the same object instance. Unfortunately, it is not possible to create an AsyncTask and call execute() more than once on the same object instance, as specified in the "Threading rules" section of the AsyncTask documentation.

The solution is to use a custom Executor to serialize the tasks, or, if you use API 11 or above, AsyncTask.executeOnExecutor(), as suggested in the comments below.

I posted an answer showing an implementation of a SerialExecutor that can be used to queue tasks that will be executed sequentially.