I have already installed 64 bit Java from here but i still get the message saying
"A 64 bit Java installation is recommended for 'Far' render distance (you have 32 bit)"
when I set the view distance to Far
If you need 32bit Java because you're a Chrome user then you can either do what jack said, launch minecraft so that it gets reassigned to the 64bit java, then reinstall 32bit java again. Another option (I think) is you might be able to just right click the launcher and modify the path to point to where the 64bit javaw.exe file is located.