Hey guys,
I've been trying to access a website to parse data for an Android application I am developing, but I am having no luck when it comes to logging in.

The website is https://giffgaff.com/mobile/login

And below is a stripped out version of the form from that page (HTML):
Java Code:
<form action="/mobile/login" method="post">
	<input type="hidden" name="login_security_token" value="b22155c7259f402f8e005a771c460670">    
	<input type="hidden" name="redirect" value="/mobile">    
	<input type="hidden" name="p_next_page" value="">    
	<input name="nickname" maxlength="25" type="text" value="" />            
	<input name="password" type="password" value="" />
	<button name="step" type="submit" value="Login"><span>Login</span></button>
Can anyone please suggest how I can login to this website using Java?

If you would like to see for yourself how the login page behaves, here's some test login details:
Nickname (username): testingA
Password: testing
The site also seems to depend on a Cookie called "napaSessionId"

Thanks for any help (: