(as per http://java.sun.com/...ex/Pattern.html)
The backslash character ('\
') serves to introduce escaped constructs, as defined in the table above, as well as to quote characters that otherwise would be interpreted as unescaped constructs. Thus the expression \\
matches a single backslash and { matches a left brace.
Other examples of usage :
\\ The backslash character<br>
\t The tab character ('\u0009')<br>
\n The newline (line feed) character ('\u000A')<br>
\r The carriage-return character ('\u000D')<br>
\f The form-feed character ('\u000C')<br>
\a The alert (bell) character ('\u0007')<br>
\e The escape character ('\u001B')<br>
\cx The control character corresponding to x <br>