So it looks like this printer supports something called ESC/POS, which is like a command set that allows you to print and format data. There are a few guides available online, this is one I've used before: http://www.starmicronics.com/support/mannualfolder/escpos_cm_en.pdf
Note that printers sometimes subtly differ in which command sets from ESC/POS they support, so you might have a bit of trial and error on your hands.
In terms of sending that data to the printer, it depends on what type of connection it is. For serial, you should just be able to open and write to that port, using the ESC/POS command set.
Not all of the data you will send will be ASCII or UTF encoded, a lot of them are binary values you need to send. So for example, to tell the printer to write a new line, the Hex value for that is 0A
. So in Java you would need to specify that as String s = "\u000A";
etc.
For java you will need to download the Java Comm API from http://java.sun.com/products/javacomm/
There is a tutorial on this here: http://www.java-samples.com/showtutorial.php?tutorialid=214
Hopefully this helps.