How to program a timecapsule app?

[AC Question]

For example I am going to register in somewhere and acidentally my browser or system crashing in android. So I would like to know how to program an app which helps to revert a saved point into tabs. Visitor only have to retype the secret code which means that the recent information is already reactivated. Which language I should learn: java/c++/javascript or should I have to learn something else. Any sites or examples are welcome about the documentation style.

 

[UJ95x]

For learning how to write apps, or at least finding resources, I'd suggest StackOverflow. Android apps are made in several different languages, but one might be more viable than another for achieving certain tasks.