Q:

What will an appended text file look like in Java?

When in Java, I append text to the end of a text file using FileWriter. Will this new text be on the direct next line of the file or will it leave a line between the old text and new text. 
Presuming my raw data has no new lines and i just rely on the "FileWriter" to append the text.
This is a simple question but is important in what i am trying to attempt. 
For example:
Is it this: (no line gap)
old data is here
new data is here

this: (line gap)
old data is here

new data is here

or even this: (Turns out this is the correct one)
old data is herenew data is here

I presume it is either one of these.

A:

Will this new text be on the direct next line of the file or will it leave a line between the old text and new text.

Answer: Yes.
It will all depend on how you've written your code, and whether or not there's a new line char at the end of the file.
It could be:
old datanew data

or 
old data
new data

or 
old data

new data

The new data will start writing immediately after the old data ends.
The best answer is as per Sotirios's comment: you should try it out for yourself, experiment with your code. Play with your code.

Edit
Given this:

Presuming my raw data has no new lines and i just rely on the "FileWriter" to append the text.

Then the answer is
old datanew data

