ServletPrintWriter.println() is using the LF(\n) as the line separator.

    public void println() {
        print('\n');
    }

I think it is better to use the system property line.separator as well as the PrintWriter class which is extended class.

https://docs.oracle.com/javase/8/docs/api/java/io/PrintWriter.html#println--
public void println()
Terminates the current line by writing the line separator string. The line separator string is defined by the system property line.separator, and is not necessarily a single newline character ('\n').