The type Font is ambiguous where generating pdf file from jsp page

I am geeting ambiguous error .Do u want to add any jar files


<%@page import="java.io.*"%>
<%@page import="java.awt.*"%>
<%@page import="com.lowagie.text.*"%>
<%@page import="com.lowagie.text.pdf.*"%>
<%
try {
Document document=new Document();
Font headFont = FontFactory.getFont(FontFactory.HELVETICA, 10,
Font.BOLD, new Color(255, 255, 255));

PdfWriter.getInstance(document,new FileOutputStream("C:/hello.pdf"));
document.open();
Table datatable = new Table(1);
datatable.addCell(new Phrase("Screen", headFont));
document.add(datatable);
document.close();
}
catch (Exception e2) {
System.out.println(e2.getMessage());
}
%>