I'm asking this because Libre Office was pre-installed and some of it's features require Java. I don't want Java because of a malicious remote administration tool (RAT) called jRAT and there are also others. But with this even a script kiddie can take control of my computer.
Simple answer, Java is not installed by default in any Ubuntu system (in fact this goes against the Java distribution policy, that's why is being included in the non-free repository).
You can check the packages manifest of any version of Ubuntu, and you will notice that it does not include either JDK nor Java.
Precise Pangolin package manifest:
Raring Ringtail package manifest:
(Links are thanks to our friend Oli)
Hope this address all inquiries.