WhatsApp is a cross platform messenger will allow you to send messages to your contacts (If they have this installed on their devices). This is available on iPhone, BlackBerry, Android, Windows Phone and Nokia phones. It supports creating chat groups too. So if you want to get the application you can visit the home page here
Whatsapp Lockers - WhatsApp lockers will allow you to password protect your WhatsApp so that no one can use it with out knowing the password.
1. WhatsApp Lock Keep privacy
It's free and has no limitations.
Lock WhatsApp with a 4 digit pin
set auto lock time
Wrong pin will take the photo of the one who is attempting (if the device have a front camera)
Design attractive and simple user interface.
Get it from Play Store
2. Messenger App Lock
It will lock your WhatsApp with a pattern.
This application will add some shortcuts on your home screen, you can delete them, without any issues.
Play Store link
3.Lock for WhatsApp widget
Password lock whatsApp
Set lock time
Get it from Google Play Store