Problem with Session.get

[muhviehstarr]

Hi,

I've got a really strange problem.

I've defined the following EntityBean:

package de.hotware.dataobjects.entities;

import java.io.Serializable;
import java.util.Collection;

import javax.persistence.Basic;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import javax.persistence.AccessType;

@Entity(access = AccessType.FIELD)
@Table(name = "categories")
public class Category implements Serializable {
 @Id(generate = GeneratorType.IDENTITY)
 @Column(name = "id")
 private int id;

 @Basic(optional = false)
 @Column(name = "foreignid", length = 10)
 private String networkId;

 @OneToOne(optional = false, fetch = FetchType.LAZY)
 @JoinColumn(name = "foreigner", nullable = false)
 private AffiliateNetwork network;

 @Basic(optional = false)
 @Column(name = "name", nullable = false)
 private String name;

 @OneToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "parent")
 private Category parent;

 @OneToMany(mappedBy = "parent")
 private Collection<Category> subcategories;

 @Override
 public boolean equals(Object obj) {
 if (!(obj instanceof Category))
 return false;
 Category o = (Category) obj;
 return o.id == id;
 }

 public int getId() {
 return id;
 }

 public void setId(int id) {
 this.id = id;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public AffiliateNetwork getNetwork() {
 return network;
 }

 public void setNetwork(AffiliateNetwork network) {
 this.network = network;
 }

 public String getNetworkId() {
 return networkId;
 }

 public void setNetworkId(String networkId) {
 this.networkId = networkId;
 }

 public Category getParent() {
 return parent;
 }

 public void setParent(Category parent) {
 this.parent = parent;
 }

 public Collection<Category> getSubcategories() {
 return subcategories;
 }

 public void setSubcategories(Collection<Category> subcategories) {
 this.subcategories = subcategories;
 }

}

And in the Sessionbean I want to search for an entity:

@Stateless
@Remote( { TestBean.class })
public class TestBeanBean implements TestBean {
 @PersistenceContext(unitName = "hotwaredb")
 private Session em;

 public Category test() {
 return (Category) em.get(Category.class, 1);
 }
}

The remote-client calls the test-method and the result is null. But the entity with id 1 exists in the database.

This is the Output of JBOSS:

22:28:48,307 DEBUG [DefaultLoadEventListener -- org.hibernate.event.def.DefaultLoadEventListener] loading entity: [dataobjects.entities.Category#1]
22:28:48,307 DEBUG [DefaultLoadEventListener -- org.hibernate.event.def.DefaultLoadEventListener] attempting to resolve: [dataobjects.entities.Category#1]
22:28:48,308 DEBUG [DefaultLoadEventListener -- org.hibernate.event.def.DefaultLoadEventListener] object not resolved in any cache: [dataobjects.entities.Category#1]
22:28:48,308 DEBUG [AbstractEntityPersister -- org.hibernate.persister.entity.AbstractEntityPersister] Fetching entity: [dataobjects.entities.Category#1]
22:28:48,309 DEBUG [Loader -- org.hibernate.loader.Loader] loading entity: [dataobjects.entities.Category#1]
22:28:48,309 DEBUG [AbstractBatcher -- org.hibernate.jdbc.AbstractBatcher] about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
22:28:48,311 DEBUG [ConnectionManager -- org.hibernate.jdbc.ConnectionManager] opening JDBC connection
22:28:48,312 DEBUG [SQL -- org.hibernate.jdbc.AbstractBatcher] select category0_.id as id74_0_, category0_.foreignid as foreignid74_0_, category0_.foreigner as foreigner74_0_, category0_.name as name74_0_, category0_.parent as parent74_0_ from categories category0_ where category0_.id=?
22:28:48,313 INFO [STDOUT -- org.jboss.logging.util.LoggerStream] Hibernate: select category0_.id as id74_0_, category0_.foreignid as foreignid74_0_, category0_.foreigner as foreigner74_0_, category0_.name as name74_0_, category0_.parent as parent74_0_ from categories category0_ where category0_.id=?
22:28:48,313 DEBUG [AbstractBatcher -- org.hibernate.jdbc.AbstractBatcher] preparing statement
22:28:48,315 DEBUG [IntegerType -- org.hibernate.type.NullableType] binding '1' to parameter: 1
22:28:48,317 DEBUG [AbstractBatcher -- org.hibernate.jdbc.AbstractBatcher] about to open ResultSet (open ResultSets: 0, globally: 0)
22:28:48,318 DEBUG [Loader -- org.hibernate.loader.Loader] processing result set
22:28:48,319 DEBUG [Loader -- org.hibernate.loader.Loader] done processing result set (0 rows)
22:28:48,319 DEBUG [AbstractBatcher -- org.hibernate.jdbc.AbstractBatcher] about to close ResultSet (open ResultSets: 1, globally: 1)
22:28:48,320 DEBUG [AbstractBatcher -- org.hibernate.jdbc.AbstractBatcher] about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
22:28:48,321 DEBUG [AbstractBatcher -- org.hibernate.jdbc.AbstractBatcher] closing statement
22:28:48,322 DEBUG [ConnectionManager -- org.hibernate.jdbc.ConnectionManager] aggressively releasing JDBC connection
22:28:48,323 DEBUG [ConnectionManager -- org.hibernate.jdbc.ConnectionManager] closing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
22:28:48,323 DEBUG [Loader -- org.hibernate.loader.Loader] total objects hydrated: 0
22:28:48,324 DEBUG [StatefulPersistenceContext -- org.hibernate.engine.StatefulPersistenceContext] initializing non-lazy collections
22:28:48,324 DEBUG [Loader -- org.hibernate.loader.Loader] done entity load
22:28:48,325 DEBUG [CacheSynchronization -- org.hibernate.transaction.CacheSynchronization] transaction before completion callback
22:28:48,326 DEBUG [JDBCContext -- org.hibernate.jdbc.JDBCContext] before transaction completion
22:28:48,327 DEBUG [SessionImpl -- org.hibernate.impl.SessionImpl] before transaction completion
22:28:48,328 DEBUG [SessionImpl -- org.hibernate.impl.SessionImpl] closing session
22:28:48,332 DEBUG [ConnectionManager -- org.hibernate.jdbc.ConnectionManager] connection already null in cleanup : no action
22:28:48,333 DEBUG [CacheSynchronization -- org.hibernate.transaction.CacheSynchronization] transaction after completion callback, status: 3
22:28:48,333 DEBUG [JDBCContext -- org.hibernate.jdbc.JDBCContext] after transaction completion
22:28:48,334 DEBUG [SessionImpl -- org.hibernate.impl.SessionImpl] after transaction completion

But the following sql-statement running directly on the server returns exactly one row:

select category0_.id as id74_0_, category0_.foreignid as foreignid74_0_, category0_.foreigner as foreigner74_0_, category0_.name as name74_0_, category0_.parent as parent74_0_ from categories category0_ where category0_.id=1

Any ideas?

Thank you for your help!

Bye Frank

[muhviehstarr]

Additional Info:

if i change the testmethod to the following code the result will not be null and also the output will be 1.

 Category uniqueResult = (Category) em.createCriteria(Category.class).setMaxResults(1).uniqueResult();
 System.out.println(uniqueResult.getId());
 return uniqueResult;

[muhviehstarr]

the problem here in detail is solved:

the current mysql-server-4.1 package of ubuntu (4.1.12) has a bug.

More Informations about the problem can be found here:
http://ubuntuforums.org/showthread.php?p=502593
or
http://forums.mysql.com/read.php?39,49989,49989#msg-49989