That is normal. Old OSX versions I think just came with Java 6 and everything else one could install themselves.
Yosemite doesn't have the 6 anymore and if you install 8U25 now you have only that.
Here you can download it and install 6 again if you need it.
You can also go setup the symlinks in versions folder again.
cd /System/Library/Frameworks/JavaVM.frameworks/Versions
set up the symlinks with folder names 1.6.0 and so on to the location of the jdk. I would set the currentJDK to the 1.8. No reason not to use that on default.
JDK 8 installs to /Library/Java/JavaVirtualMachines/
JDK 6 you find in /System/Library/Java/JavaVirtualMachines/
Don't ask me why but that is where they ended up on my MBP.
BTW I almost forgot you can run AndroidStudio with Java 8 and in my experience it works well enough and text rendering is sharper.
Go to the Applications folder -> click Android Studio -> show package contents
navigate to Contents and click info.plist
on the bottom under JVMOptions go to JVMVersion and replace the "1.6" with "1.8*".
Start Android studio and check out how different it looks.