Efficient way to monitor an online database in android

I'm currently working on a project that involves an Android App running on my phone and a Java App running on my laptop.

The Java App needs to update an online database periodically and the Android app needs to periodically query that database too.

I was thinking of uploading a php page (web service?) that when accessed it returns the value of the needed data (in json).

Also, I will have an activity in the app that will run a thread that will periodically send an Http Request to the said php page, and then do something with the response. What's the best approach for this?