Create a new line in Java’s FileWriter

If you want to get new line characters used in current OS like \r\n for Windows, you can get them by

• System.getProperty("line.separator");
• since Java7 System.lineSeparator()
• or as mentioned by Stewart generate them via String.format("%n");

---

You can also use PrintStream and its println method which will add OS dependent line separator at the end of your string automatically

PrintStream fileStream = new PrintStream(new File("file.txt"));
fileStream.println("your data");
//         ^^^^^^^ will add OS line separator after data 

(BTW System.out is also instance of PrintStream).