public String getFileExtension() {
		String lastSegment = getLastSegment();
		int idx = lastSegment.lastIndexOf('.');
		if (idx == -1) {
			return null;
		}
		return lastSegment.substring(idx+1);
	}
public String getFileExtension ( ) { String lastSegment = getLastSegment ( ) ; int idx = lastSegment . lastIndexOf ( '.' ) ; if ( idx == - 1 ) { return null ; } return lastSegment . substring ( idx + 1 ) ; }
@return the file extension or <code>null</code> if this path's last segment doesn't have a file extension.