Does java `SingleThreadExecutor` guarantee previous work is finished before new one starts?

Question

This is fragment of my code:

AppExecutors.getInstance().diskIO().execute(new Runnable() {
    @Override
    public void run() {
        // work 1
    }
});

JSONArray apiResponseGet = ApiHelper.getInstance().getData();

if(apiResponseGet == null)
    throw new Exception("Api call failed");

AppExecutors.getInstance().diskIO().execute(new Runnable() {
    @Override
    public void run() {
        // work 2
    }
});

What I except this code to do is to launch work 1, then, while work 1 is executing, make request to api, and after api call finishes save it's results in work 2.
The problem here is that work 2 has to be executed after work 1 is done. If work 2 would start before work 1 is finished, this could cause my app to misbehave.

Usually call to API will take much longer than work 1, but let's assume for now that api call has finished, and work 1 is still running. Since diskIO is SingleThreadExecutor, does that mean, that since it's single thread, in this case work 2 will have to wait until work 1 finishes?
And if answer is no, how to make sure that when work 2 starts, work 1 is already done?

Answer 1

From SingleThreadExecutor:

Tasks are guaranteed to execute sequentially, and no more than one task will be active at any given time.

So in your case work 2 will have to wait until work 1 finishes.