my phone blacked out because of some application locker application.

[AC Question]

i received an application locker from a friend once i turned it on it locked my phone what should i do

 

[belodion]

Can you boot into Safe Mode?

 

[B. Diddy]

Welcome to Android Central! Which phone? What do you mean when you say you received an application locker from a friend? Did you install it from the Google Play Store, based on your friend's recommendation? If so, did you create a password for the app? Or did it just suddenly lock you out of the phone? If the latter, I would guess it's a malicious app, or else your "friend" is playing a childish prank on you.