Send calendar invite per email with java -

i'm trying send calendar invites per email java. recipient gets email instead of being shown invitation accept or decline, event automatically added calendar.

i'm building event/invite ical4j.jar

private calendar getinvite(session session) {     calendar calendar = new calendar();     calendar.getproperties().add(version.version_2_0);     calendar.getproperties().add(method.request);      vevent event = new vevent(         new datetime(sesion.getstartdate()),          new datetime(sesion.getenddate()),          session.getname());      event.getproperties().add(priority.medium);     event.getproperties().add(clazz.public);      try {         uidgenerator ug = new uidgenerator("uidgen");         uid uid = ug.generateuid();         event.getproperties().add(uid);     } catch (socketexception e) {         // log things     }      (participant participant : session.getparticipants()) {         attendee attendee = new attendee(uri.create("mailto:" + participant.getemail()));         attendee.getparameters().add(role.opt_participant);         attendee.getparameters().add(new cn(participant.getname()));         attendee.getparameters().add(partstat.needs_action);         event.getproperties().add(attendee);     }      calendar.getcomponents().add(event);      return calendar;  } 

and how send email:

public void sendemail(string frommail, string tomail, string subject, string text, net.fortuna.ical4j.model.calendar calendar) {     try {         session session = session.getinstance(getmailproperties(), new javax.mail.authenticator() {             protected passwordauthentication getpasswordauthentication() {                 return new passwordauthentication(getuser(), getpassword());             }         });          mimemessage mimemessage = new mimemessage(session);         mimemessage.setheader("content-transfer-encoding:", "7bit");          address address = new internetaddress(frommail);         mimemessage.setfrom(address);          mimemessage.setsentdate(calendar.getinstance().gettime());         mimemessage.setrecipients(message.recipienttype.to, tomail);          mimemessage.setsubject(subject);         calendar cal = calendar.getinstance();         mimemessage.setsentdate(cal.gettime());          multipart multipart = new mimemultipart("alternative");          // first part - html readable text           mimebodypart msghtml = new mimebodypart();         msghtml.setcontent(text, "text/html; charset=utf-8");          multipart.addbodypart(msghtml);          if (calendar != null) {             // part calendar invite             mimebodypart invite = new mimebodypart();             invite.setheader("content-class", "urn:content-  classes:calendarmessage");             invite.setheader("content-id", "calendar_message");             invite.setheader("content-disposition", "inline");             invite.setcontent(calendar.tostring(), "text/calendar");             multipart.addbodypart(invite);         }          mimemessage.setcontent(multipart);          transport.send(mimemessage);      } catch (exception e) {         // log things     }  } 

but when email (in gmail), see no invitation, event automatically added calendar. can accept or decline clicking on event in calendar.

i have tried send invite, happens email ics attachment.

what missing?

you creating new calendar, that's why calendar added automatically. see documentation https://github.com/ical4j/ical4j/wiki/examples#creating_a_new_calendar try "creating meeting of 4 hour duration" , see if still have problem.