Bibliography is not working

I’m trying to use the bibliography feature on libre office. When I go to Tools then Biography Database, I get a message to restart LibreWriter. This is all it does, I also get a message from Ubuntu, that LibreWriter is checking the repository for software, but it shows none available. Is there another way for add ons? How do I check the software is complete?

The bibliographic database relies on Base, and that component needs a java runtime environment running. Over the years I’ve seen many LibO users in *ubuntu with problems related to the java engine and / or the Base component not installed. Check with your package administration tool if a package called libreoffice-base or something like that is already installed. Check also that you have a valid java runtime environment available on your system and that it is selected under Tools → Options → LibreOffice → Advanced.

Thanks, I looked it up and I don’t see runtime. How do I install it?

I don’t use ubuntu, so I cannot provide a step by step procedure, but open your software administration tool and look for something like java-1_8_0-openjdk or similar.