According to
the API for PrintStream (System.out is a PrintStream object), the println() method will "Terminate 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')."
However, the problem is that if your console is 80 characters wide and you write to the 80th character, many consoles will start a new line for you. Since you also start a new line, you get double spaced lines. The important thing is that different operating systems will behave differently, so don't depend on that behavior.