Here is the one solution for this
try {
MimeMessage message = new MimeMessage(session);
message.setFrom(new InternetAddress("sender@emailID.com"));
message.addRecipient(Message.RecipientType.TO, new InternetAddress("recepint@emailID.com"));
message.setSubject("Hello iCal4j Meeting Invitation");
// create the message part
MimeBodyPart messageBodyPart = new MimeBodyPart();
// fill message
messageBodyPart.setText("Hi Sir, Please see the demo example to send meeting invitaiton from iCal4j API.");
Multipart multipart = new MimeMultipart();
multipart.addBodyPart(messageBodyPart);
// Part two is attachment
messageBodyPart = new MimeBodyPart();
DataSource source = new FileDataSource(calFile);
messageBodyPart.setDataHandler(new DataHandler(source));
messageBodyPart.setFileName(calFile);
multipart.addBodyPart(messageBodyPart);
// Put parts in message
message.setContent(multipart);
Transport.send(message);
// System.out.println(meeting);
} catch (MessagingException e) {
throw new RuntimeException(e);
}