java - Session not working on GAE server, only locally -

i have google app engine (java) project i'm trying use sessions. in appengine-web.xml file have

<sessions-enabled>true</sessions-enabled> 

. have userendpoint class has api method called "login". if user that's trying login app legit create session inside method:

httpsession session = req.getsession(); session.setattribute("userid", new longbean(user.getid().longvalue())); 

the longbean object serializable , looks like:

public class longbean implements serializable {     private static final long serialversionuid = 8041280664162299553l;      private long longvalue;      public longbean(long longvalue) {         this.longvalue = longvalue;     }      public long getlongvalue() {         return longvalue;     }      public void setlongvalue(long longvalue) {         this.longvalue = longvalue;     } } 

. now, have api method in endpoint called insertscore. there check if session not null , has correct "userid" attribute. signature method is:

public userscore insertscore(         httpservletrequest req,         score score) throws notfoundexception, forbiddenexception 

and

object userid = req.getsession().getattribute("userid"); 

. problem userid object null when project deployed on google's servers. makes more infuriating works locally. i've searched stackoverflow issue , answers i've found session has serializable longbean object seralizable! explain why works on localhost not on server?

edit: info: can see in datastore viewer session created , inserted _ah_session table in datastore.

adding

auth = @apiauth(allowcookieauth = annotationboolean.true) 

to @api annotation in endpoint allows jsessionid cookie sent on wire, fixing issue.