Android 5.5.1 How to implement the output messages after starting the system without writing an application?

Actually, the problem in the title.

The easiest way, in my opinion, looks like the application that when run displays the message specified in its settings. Itself be the application run by the application to startup. The application to autorun on playmarket I found, and the application displays a message when it starts up - no.

I would be glad if you tell me such application or other simple way of solving the problem. Thanks in advance.

PS the message I understand the dialog with the "OK"button.