Note:- This will void warranty of your device.

Okay , now to root a sony xperia first go to 

1. settings->security->tick unknown sources

2. settings->developer option->tick USB debugging

3.settings->Xperia->connectivity->Usb connecting mode and change it to  MSC .(after rooting change back to MTP).

4. Go to this MEDIAFIRE link and download eroot.

Now connect your phone with pc using USB cable and open e root first it will show you the name of your phone and then at bottom there will be written "ROOT" just click on that wait and when its over go to your phone's menu and look for a "superuser" icon if it is there then your phone is rooted if not repeat these steps. The language of the software is Chinese or Japenese but root is written in english and that's what you have to click on .

Thanks.