hibernate - How to get actual entity type from JPA based entries without fetching all object -


i need actual entity type jpa based entries without fetching object. example there 2 entities - superuser extends user.

and want 

id  type 1   com.company.domain.superuser    2   com.company.domain.user

situation:

user 

@table(name = "users") @discriminatorvalue(value = "user") @inheritance(strategy= inheritancetype.single_table) @entity public class user implements serializable {     private static final long serialversionuid = 1l;     @id     @generatedvalue(strategy=generationtype.auto)     private long id;      public long getid() {         return id;     }     public void setid(long id) {         this.id = id;     } }

super user

@discriminatorvalue(value = "superuser") @entity public class superuser extends user implements serializable {      private static final long serialversionuid = 2l; }

current entries data

insert users(dtype, id) values('superuser',1); insert users(dtype, id) values('user',2);

i'm trying entity class , column id nullpointerexception. i'm doing wrong?

entitymanagerfactory entitymanagerfactory = persistence.createentitymanagerfactory("persistence"); entitymanager entitymanager = entitymanagerfactory.createentitymanager();  query query;  //works query = entitymanager.createquery("select type(us), us.id user type(us) = 'superuser'"); query.getresultlist(); //works query = entitymanager.createquery("select type(us), us.id superuser us"); query.getresultlist();  //throws npe query = entitymanager.createquery("select type(us), us.id user type(us) = 'user'"); query.getresultlist(); //throws npe query = entitymanager.createquery("select type(us), us.id user us"); query.getresultlist();

update: adding stacktrace:

exception in thread "main" java.lang.nullpointerexception     @ org.hibernate.tuple.entity.pojoentitytuplizer.determineconcretesubclassentityname(pojoentitytuplizer.java:333)     @ org.hibernate.persister.entity.abstractentitypersister.getsubclassentitypersister(abstractentitypersister.java:4581)     @ org.hibernate.internal.sessionimpl.getentitypersister(sessionimpl.java:1456)     @ org.hibernate.persister.entity.discriminatortype.nullsafeget(discriminatortype.java:72)     @ org.hibernate.persister.entity.discriminatortype.nullsafeget(discriminatortype.java:59)     @ org.hibernate.loader.hql.queryloader.getresultrow(queryloader.java:452)     @ org.hibernate.loader.hql.queryloader.getresultcolumnorrow(queryloader.java:435)     @ org.hibernate.loader.loader.getrowfromresultset(loader.java:756)     @ org.hibernate.loader.loader.processresultset(loader.java:972)     @ org.hibernate.loader.loader.doquery(loader.java:930)     @ org.hibernate.loader.loader.doqueryandinitializenonlazycollections(loader.java:336)     @ org.hibernate.loader.loader.dolist(loader.java:2611)     @ org.hibernate.loader.loader.dolist(loader.java:2594)     @ org.hibernate.loader.loader.listignorequerycache(loader.java:2423)     @ org.hibernate.loader.loader.list(loader.java:2418)     @ org.hibernate.loader.hql.queryloader.list(queryloader.java:501)     @ org.hibernate.hql.internal.ast.querytranslatorimpl.list(querytranslatorimpl.java:371)     @ org.hibernate.engine.query.spi.hqlqueryplan.performlist(hqlqueryplan.java:220)     @ org.hibernate.internal.sessionimpl.list(sessionimpl.java:1268)     @ org.hibernate.internal.queryimpl.list(queryimpl.java:87)     @ org.hibernate.jpa.internal.queryimpl.list(queryimpl.java:567)     @ org.hibernate.jpa.internal.queryimpl.getresultlist(queryimpl.java:436)     @ com.geowarin.hibernate.jpa.standalone.app.tryfetch(app.java:40)     @ com.geowarin.hibernate.jpa.standalone.app.main(app.java:19)


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