Thank you for your post.
FileMaker Server 16 should install a version of Java on the machine. If you are getting an error that Java wasn't installed, then it appears either the installation was incomplete, or something happened to the Java installation.
Did you install FileMaker Server 16 on the Mac with a Mac Admin account?
From the Admin Console, are all services running?
Does the Event.log list any other errors besides the Backup errors?
That install ran for a day or so before I bailed. Externally stored secure containers had became unwritable.
I had installed with the admin account, and the services were all running. I don't recall any other errors in the log.
I eventually un-installed and re-installed. In between, however, I made Chrome the default browser, and that change seems to have allowed the Java installation to proceed unimpaired. The server is now working fine.
So, it seems like a bug that FMS 16 won't install Java on a box where Safari is the default browser.
Following your guidelines, I found a machine with macOS Sierra 10.12.5, and made sure Safari (10.11.1) was the default browser. I then successfully installed FileMaker Server 16. I then manually ran the default Backup schedule, and it worked properly. I also created a new Backup schedule, ran it, and it worked properly. Therefore, I don't believe Safari was the issue but some other factor. Regardless, I am glad it is now working for you.
Wow-- thank you for taking the time and using the resources to attempt to re-create.
When my customers present me with a glitch I cannot re-create, I tell them I'm patient, and know that it will come back. In this case, that assumes I took no detours during the installation, but I'm confident I did not.
The only environmental difference I can imagine between our two setups is that my machine was entirely virgin-- I had literally just unpacked it.
Let's see if similar anecdotes begin to appear. Hopefully my memory is wrong, and I did something odd during the install.