Hi it is possible to create a mobile app from ceros? i mean the instructions explain that you have to install an android or iphone app but i want to write java code from cero
The term cero does not ring a bell, but if you mean zero - or from scratch 
then it is absolutely possible.
There are some fellows here that have gone this way - either a web app or Android app and even a Windows Phone app is development.
You might like to do a forum search to find them.
But to get a good and firm base you might still want to have a look at the open source Android app. This is what I’ve based my own ExtTinkerApp on.
Cero is Spanish for Zero and judging from the OP’s real name, this is about right 
@tuxidomask scruffr’s suggestion to check out the open source app is the best way to find out how the WiFi communications work with the Spark Core on your local network.
If you have Java experience, then Android is basically the same except you will need to learn how to develop the views etc but it is straight forward enough if you have good programming skills and know how the find the answers. Google is a great place to search for and find loads of samples.
Good luck with it.