Opening Files in your software

Hi Everyone,

New to this sub but I just wanted to know if anyone has any idea with Java Software Development how to get your software to run differently depending on if someone has opened up a .exe file from its source of it is being opened up because a save file is requesting it to be open up and showing its data.

As with Word, when you click on Word it opens up a blank word document but if you open up a saved word document it will open up that document.

In programming terms how can you get a program to recognise how it has been opened?

Any help would be appreciated or if someone pointed me in the right direction!