I have never set any passwords to my keystore and alias, so how are they created?

Question

As I was going through some posts on the Internet learning more about signing your Android app, I got post like how to sign the app, and something

Answer 1

Keystore name: "debug.keystore"

Keystore password: "android"

Key alias: "androiddebugkey"

Key password: "android"

I use this information and successfully generate Signed APK.