Both Oracle JDK and OpenJDK are shown as Oracle Corporation

I am using LibreOffice Version: 4.2.5.2 Build ID: 4.2.5.2-9.fc20 on Fedora 20 KDE.

Yes. Oracle Corporation is the vendor / developer of OpenJDK as indicated on the Wikipedia page. The AskUbuntu answer here explains that while there were differences between the two during Java v6, under Java v7 there are now none.