I'm running AS7 on Mac, but found sometimes my servlet PrintWriter produces output with dos-style eol. When opening the output in vi, there are a couple of ^M at end of line.

This does not always happen. After trying out a few samples, I found if the line already contains line.separator, then its eol will be ^M. For example,

PrintWriter out = response.getWriter();

out.println("From " + System.getProperty("line.separator") + this);

From

test.TestServlet@180ab18^M

If line.separator is not used when constructing servlet output, then everything looks normal.

My guess is the servlet container may first apply a dos-style eol, then does some sort of replacing with native eol by searching for the first occurrence of line.separator.