java - Lazy loading property and session.get problem -

in hibernate have 2 classes following classes jpa mapping:

package com.example.hibernate  import javax.persistence.entity; import javax.persistence.fetchtype; import javax.persistence.generatedvalue; import javax.persistence.generationtype; import javax.persistence.id; import javax.persistence.manytoone;  @entity public class foo {   private long id;   private bar bar;    @id   @generatedvalue(strategy = generationtype.auto)   public long getid() {     return id;   }    public void setid(long id) {     this.id = id;   }    @manytoone(fetch = fetchtype.lazy)   public bar getbar() {     return bar;   }    public void setbar(bar bar) {     this.bar = bar;   } }  package com.example.hibernate  import javax.persistence.generatedvalue; import javax.persistence.generationtype; import javax.persistence.id;   public class bar {   private long id;   private string title;    @id   @generatedvalue(strategy = generationtype.auto)   public long getid() {     return id;   }    public void setid(long id) {     this.id = id;   }     public string gettitle() {     return title;   }    public void settitle(string title) {     this.title = title;   }  } 

now when load database object class foo using session e.g:

foo foo = (foo)session.get(foo.class, 1 /* or other id exists in db*/); bar member of foo proxy object (in our case javassist proxy can cglib 1 depending on bytecode provider use), not initialized. if use session.get fetch bar object member of foo class loaded (we in same session), hibernate not issue db query , fetches object session (first level) cache. problem proxy bar class not initialized , trying call object getid() return 0, , gettitle() return null. our current solution pretty ugly , checks if object returned proxy here code (form generic dao implementation):

@suppresswarnings("unchecked") @override @transactional(readonly = true) public <t extends ientity> t get(class<t> clazz, serializable primarykey) throws dataaccessexception {   t entity = (t) currentsession().get(clazz, primarykey);   if (entity != null) {     if (log.iswarnenabled()) {       log.warn("object not found class " + clazz.getname() + " primary key " + primarykey);     }   } else if (entity instanceof hibernateproxy){ // todo: force initialization due hibernate bug     hibernateproxy proxy = (hibernateproxy)entity;     if (!hibernate.isinitialized(proxy)) {       hibernate.initialize(proxy);     }     entity = (t)proxy.gethibernatelazyinitializer().getimplementation();   }   return entity; } 

is there better way this, couldn't find solution in hibernate forum, , didn't find issue in hibernate's jira.

note: cannot use foo.getbar() (which initialize proxy properly) bar class object, because session.get operation fetch bar object not know (or care matter) bar class lazy member of foo object fetched.

i had similar problem:

• i did session.save(nastyitem) save object session. however, did not fill in property buyer mapped update="false" insert="false" (this happens lot when have composed primary key, map many-to-one's insert="false" update="false")
• i query load list of items, , item saved, happens part of result set
• now goes wrong? hibernate sees item in cache, , hibernate not replace (probably not break earlier reference nastyitem) newly loaded value, uses nastyitem have put session cache myself. worse, lazy loading of buyer broken: contains null.

to avoid these session issues, flush , clear after save, merge, update or delete. having solve these nasty problems takes of time :-(