running mac os 10.12.4
64 bit
installed java version 1.8.0_121
error message always comes up ‘java inst not found’
going to libreoffice preferences > advanced > java options - “use java runtime environment” box is checked,
“JRE already installed” box shows none
tried clicking “add” box, found location but location for java not accepted
it’s all too cryptic for me
Mac requires use of JDK and NOT JRE. Please install latest JDK from Oracle.
If the answer solves your question please tick the 
.
I am running windows 10 64 bit and JRE 1.8.0_32 installed - The run JRE environment is checked. I get the message " No Java installation could be found". Please check your installation.
Version: 5.4.3.2 (x64)
Your message is not an answer to original question! (Even without taking into account that you are talking about Windows, while original question is about macOS.)
You must use 64-bit Java for 64-bit LibreOffice. Install the 64-bit Java. (You may keep 32-bit one, no need to remove it in case you also need it e.g. for other apps.)