Exemplo

public static void main( String[] args) { FileWriter fw = null; try { fw = new FileWriter( "LineSeparators.txt" ); //$NON-NLS-1$ fw.write( "Hello World!" ); //$NON-NLS-1$ fw.write("\n");//$NON-NLS-1$ }catch (Exception e){ e.printStackTrace(); } finally { if ( fw != null ) { try { fw.close(); } catch ( Exception e ) {} } } }

Solução

Utilize System.getProperty( "line.separator" ). public static void main( String[] args) { FileWriter fw = null; try { fw = new FileWriter( "LineSeparators.txt" ); //$NON-NLS-1$ fw.write( "Hello World!" ); //$NON-NLS-1$ fw.write( System.getProperty( "line.separator" ) ); //$NON-NLS-1$ }catch (Exception e){ e.printStackTrace(); } finally { if ( fw != null ) { try { fw.close(); } catch ( Exception e ) {} } } }