LibreOffice requires a 64-bit Java runtime environment (JRE) to perform this task.

LibreOffice requires a 64-bit Java runtime environment (JRE) to perform this task. Please install a JRE and restart LibreOffice. I started to get this message recently. When I click okay, Libre Office starts. Why?
Thank you.

to perform this task.

And it does not mention which task? Have you installed an extension requiring Java recently? Which LibreOffice version do you use on which operating system? Are you using Base with HSQLDB?

Check also FAQ - What is Java used for in LibreOffice and if something from the list applies to your system.

Regarding your “Answer”: You are not willing to tell anything, your are not willing to cooperate and you just insist that it does not work as before, which doesn’t pave a road to any solution - hence help yourself.

I get this message at startup invariably in recent versions (now using 6.4.7.2 x64). Doesn’t make the app unusable; I just dismiss the dialog and continue. Still, it’s concerning. I’m afraid I will run into a feature that is unusable because of this. I regularly install Sun JRE updates in Windows 10.

I use 6.3.6.2. I did not have this problem prior to upgrading to the version. I never had to click on the pop-up. I have the latest version of 64-bit Java runtime environment. JRE. I do not understand the need to suddenly have to go through these machinations or the extra step. Not sure what you mean when you say which task. I am using the equivalent to MS Word. Any help appreciated.
Thanks.

This is not an answer to the question.

You should edit this into your original question or post this as a comment.