I haven't been able to find the answer to
this in the books I have, though I suspect it is fairly common.

I have a text file I want to insert into at a specific location. I want to
insert text exactly one line above the final line of the file. So, for
example, if the file ends with ###, I want to look for that, then insert
text one line above.

I've already figured that I need to use RandomAccessFile, but I'm not sure
how, exactly. Any clues or pointers to help would be greatly appreciated.