For example, if user installed app in more than one devices, and he tries to login from all devices at a same time then I want to restrict him to not to login from any other devices until he going to logout from first device. Only one active login at a time.
How to achieve above from IBM Worklight 6.1 ? Any API are available for same from Client or Adapter side ? Please let me Know.
There is not built-in feature per-se in Worklight that will give you what you want.
What you could do is explore the world of Custom Authenticators and Login Modules.
You will likely need to create custom properties stored in the database, allowing you to identify if a user is already "logged-in", in which case could perhaps either show a message to the user, or have him force-logout.
Either way, you should probably not stick with Worklight 6.1 - that is an extremely old version.