Getting nullpointer exception while executing query in JPA using Hibernate 5.1.2 as JPA vendor -

i'm trying upgrade application openjpa implementation 1.0.1 using jpa 1.0 hibernate 5.1.2

i'm getting nullpointer exception when trying to call geresultlist on entity class.

my sample classes below: (i've changed class names can not share original source code. mapping same.)

1) class charger (representing sort of mobile charger has 2 pin)

@entity @table(name = "charger") class chargerentityext5 extends chargerentity1abstract implements serializable {  @transient private static final long serialversionuid = -1l;  @onetomany(mappedby="chargerentityext5",targetentity=portentityext5.class,         fetch=fetchtype.eager) @fetch(value = fetchmode.subselect) public list<pinentityext5> pinentityextlist;  public list<pinentityext5> getpinentityextlist() {     return pinentityextlist; }  public void setpinentityextlist(list<pinentityext5> pinentityextlist) {     this.pinentityextlist = pinentityextlist; }   } 

2)

@mappedsuperclass class chargerentity1abstract implements serializable {  private static final long serialversionuid = 1l;  @id @column(name="id") public long id;  @column(name="charger_id") public string chargerid;   // *** constructor **** public chargerentity1abstract() { }  @override public string tostring() {     return "chargerentity [cpeid=" + id!=null? id.tostring():""  +              ", chargerid=" + chargerid!=null? chargerid.tostring():""  + "]"; }  public long getid() {     return id; }  public void setid(long id) {     id = id; }  public string getchargerid() {     return chargerid; }  public void setchargerid(string chargerid) {     this.chargerid = chargerid; }   } 

3) every charger has 2 pins i've declared bi-directional 1 many mapping between charger , pin.

@entity @table(name = "pin") class pinentityext5 extends pinentity1abstract implements serializable{  @transient private static final long serialversionuid = -1l;  @manytoone(optional=false) @notfound(action = notfoundaction.ignore) @joincolumn(name="charger_id", referencedcolumnname="charger_id",  insertable= false, updatable = false) private chargerentityext5 chargerentityext5;  public chargerentityext5 getchargerentityext5() {     return chargerentityext5; }  public void setchargerentityext5(chargerentityext5 chargerentityext5) {     this.chargerentityext5 = chargerentityext5; }  } 

4) pin entity has 2 properties. charger_id , pin_number. 2 field defines 1 record in pin table uniquely. i've declared idclass (chargerpin) representing composite key

@mappedsuperclass @idclass(chargerpin.class) class pinentity1abstract implements serializable{  @transient private static final long serialversionuid = 1l;  @id @column(name="charger_id", nullable = true) public string chargerid;  @id @column(name="pin_number", nullable = true) public long pin;  public pinentity1abstract() { }   @override public string tostring() {     return "pinentity [chargerid=" + chargerid +              ", port=" + pin!=null? pin.tostring():""  + "]"; }   public string getchargerid() {     return chargerid; }   public void setchargerid(string chargerid) {     this.chargerid = chargerid; }   public long getpin() {     return pin; }   public void setpin(long pin) {     this.pin = pin; }  }    class chargerpin implements java.io.serializable{  @transient private static final long serialversionuid = 1l;  private string chargerid;  private long pin;  // **** constructor ***** public chargerpin() { }  public chargerpin(string kapid, long port) {     this.chargerid = kapid;     this.pin = port; }    @override public string tostring() {     return "kapid [chargerid=" + chargerid!=null? chargerid.tostring():"" +             ", port=" + pin!=null? pin.tostring():""  + "]"; }  @override public int hashcode() {      final int prime = 31;     int result = 1;     int kap = chargerid != null ?(integer.parseint(chargerid)):0;     int kap_port = pin!=null?(pin).intvalue():0;     result = prime * result + kap;     result = prime * result + kap_port;     return result;  }  @override public boolean equals(object obj) {     //return ((o instanceof cpeport) && (kapid.equalsignorecase(((cpeport) o).getkapid())) && (port == (((cpeport) o).getport())));     if (this == obj)         return true;     if (obj == null)         return false;     if (!(obj instanceof cpeport1))         return false;     chargerpin other = (chargerpin) obj;     if (chargerid == null) {         if (other.chargerid != null)             return false;     } else if ((other.chargerid != null) && chargerid.equals(other.chargerid)) {         return false;     }      if (pin == null) {         if (other.pin != null)             return false;     } else if ((other.pin != null) && (pin != other.pin))         return false;      return true; }  public string getchargerid() {     return chargerid; }  public void setchargerid(string chargerid) {     this.chargerid = chargerid; }  public long getpin() {     return pin; }  public void setpin(long pin) {     this.pin = pin; }  } 

5) while i'm invoking below query i'm getting nullpointer exception empty satck trace.

public class hibernatetestclass {  /**  * @param args  */  public static entitymanagerfactory entitymanagerfactory;  public static void main(string[] args) {     // todo auto-generated method stub      entitymanager em = null;      list<chargerentityext5> chargerlist = null;      query query = null;     string querystring = "select ce chargerentityext5 ce ce.chargerid=?1";     try {          try {             em = createentitymanager();         } catch (exception e) {             system.out.println(e);         }          query = em.createquery(querystring);         query.setparameter(1, "110284026");         chargerlist = query.getresultlist();         system.out.println(chargerlist.size());      } catch (illegalstateexception e) {         system.out.println(e);     } catch (illegalargumentexception e) {         system.out.println(e);     } catch (exception e) {         system.out.println(e);      } finally{         em.close();     }      }  public static entitymanager createentitymanager() {      entitymanagerfactory =     persistence.createentitymanagerfactory("polcaincapu");     return entitymanagerfactory.createentitymanager(); } } 

can please bug. earlier trying hibernate 5.1.1. version , code throwing error "error accessing field reflection persistent property". changed code base use hibernate version 5.1.2 , without change of source code exception got changed nullpointer exception.

down vote

this full stack trace of exception. know why coming @ all:

java.lang.nullpointerexception @ chargerentity1abstract.tostring(embeddedidtester.java:462) @ org.hibernate.pretty.messagehelper.addidtocollectioninfostring(messagehelper.java:362) @ org.hibernate.pretty.messagehelper.collectioninfostring(messagehelper.java:333) @ org.hibernate.loader.plan.exec.process.internal.collectionreferenceinitializerimpl.finishuprow(collectionreferenceinitializerimpl.java:62) @ org.hibernate.loader.plan.exec.process.internal.abstractrowreader.readrow(abstractrowreader.java:121) @ org.hibernate.loader.plan.exec.process.internal.resultsetprocessorimpl.extractresults(resultsetprocessorimpl.java:122) @ org.hibernate.loader.plan.exec.internal.abstractloadplanbasedloader.executeload(abstractloadplanbasedloader.java:122) @ org.hibernate.loader.plan.exec.internal.abstractloadplanbasedloader.executeload(abstractloadplanbasedloader.java:86) @ org.hibernate.loader.collection.plan.abstractloadplanbasedcollectioninitializer.initialize(abstractloadplanbasedcollectioninitializer.java:88) @ org.hibernate.persister.collection.abstractcollectionpersister.initialize(abstractcollectionpersister.java:688) @ org.hibernate.event.internal.defaultinitializecollectioneventlistener.oninitializecollection(defaultinitializecollectioneventlistener.java:75) @ org.hibernate.internal.sessionimpl.initializecollection(sessionimpl.java:2004) @ org.hibernate.collection.internal.abstractpersistentcollection$4.dowork(abstractpersistentcollection.java:567) @ org.hibernate.collection.internal.abstractpersistentcollection.withtemporarysessionifneeded(abstractpersistentcollection.java:249) @ org.hibernate.collection.internal.abstractpersistentcollection.initialize(abstractpersistentcollection.java:563) @ org.hibernate.collection.internal.abstractpersistentcollection.forceinitialization(abstractpersistentcollection.java:731) @ org.hibernate.engine.internal.statefulpersistencecontext.initializenonlazycollections(statefulpersistencecontext.java:918) @ org.hibernate.loader.plan.exec.internal.abstractloadplanbasedloader.executeload(abstractloadplanbasedloader.java:149) @ org.hibernate.loader.plan.exec.internal.abstractloadplanbasedloader.executeload(abstractloadplanbasedloader.java:86) @ org.hibernate.loader.entity.plan.abstractloadplanbasedentityloader.load(abstractloadplanbasedentityloader.java:167) @ org.hibernate.persister.entity.abstractentitypersister.load(abstractentitypersister.java:4002) @ org.hibernate.event.internal.defaultloadeventlistener.loadfromdatasource(defaultloadeventlistener.java:508) @ org.hibernate.event.internal.defaultloadeventlistener.doload(defaultloadeventlistener.java:478) @ org.hibernate.event.internal.defaultloadeventlistener.load(defaultloadeventlistener.java:219) @ org.hibernate.event.internal.defaultloadeventlistener.proxyorload(defaultloadeventlistener.java:278) @ org.hibernate.event.internal.defaultloadeventlistener.doonload(defaultloadeventlistener.java:121) @ org.hibernate.event.internal.defaultloadeventlistener.onload(defaultloadeventlistener.java:89) @ org.hibernate.internal.sessionimpl.fireload(sessionimpl.java:1142) @ org.hibernate.internal.sessionimpl.access$2600(sessionimpl.java:167) @ org.hibernate.internal.sessionimpl$identifierloadaccessimpl.doload(sessionimpl.java:2762) @ org.hibernate.internal.sessionimpl$identifierloadaccessimpl.load(sessionimpl.java:2741) @ org.hibernate.internal.sessionimpl.get(sessionimpl.java:978) @ org.hibernate.jpa.spi.abstractentitymanagerimpl.find(abstractentitymanagerimpl.java:1075) @ org.hibernate.jpa.spi.abstractentitymanagerimpl.find(abstractentitymanagerimpl.java:1033) @ dk.tdc.visitation.polcalink.resource.dbresource.polcadb.inca.servingfp.embeddedidtester.main(embeddedidtester.java:47)