If you search the old forum, you will see a number of topics about printing. Which is no a simple task in Java!

yes i've found this:

http://www.javaworld.com/javaworld/jw-10-2000/jw-1020-print.html

I think it's weird that processing doesn't have a simple sollution for this.

For most printing needs, people are happy enough to export to bitmap or PDF then to print the output file.
As I wrote and as you saw, printing isn't a simple task and probably has low priority (because of above workaround...) among the other tasks to improve Processing.