Q:

Control pump via raspberry pi

I have a pump that is powered when plugged into the mains.
I have a Raspberry Pi 2 Model B running Raspbian Jessie.

How can I switch this pump on/off via software running on the raspberry pi? (Ideally Java?)
Is it possible to power this pump with multiple raspberry pi instead of using the mains?

Pump: http://www.hozelock.com/aquatics/pumps/filter-pumps/titan/titan-3000.html

A:

Question 2: NO. This pump needs 230V mains voltage (AC) ... the rPi supplies 5V and 3V3, both DC. 
Question 1 has been answered a gazillion times on this site as well as on the rest of the internet, just google for "Raspberry Pi AC pump relay" - for example this article on this site: How can one control AC power (220V) with a Raspberry Pi?

