I'm having problems exercising the following code (details below). Interestingly this works in our Linux environment but does not run out of Eclipse on Windows.

Hibernate version:
3

Mapping documents:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Apr 9, 2007 5:30:58 PM by Hibernate Tools 3.2.0.b9 -->
<hibernate-mapping>
<class name="com.transunion.ms.library.database.beans.MtrcTyp" table="MTRC_TYP">
<comment></comment>
<id name="mtrcTypId" type="int">
<column name="MTRC_TYP_ID" />
<generator class="assigned" />
</id>
<many-to-one name="mtrcDataTyp" class="com.transunion.ms.library.database.beans.MtrcDataTyp" fetch="select">
<column name="DATA_TYP_ID">
<comment></comment>
</column>
</many-to-one>
<!--
<many-to-one name="mtrcTyp" class="com.transunion.ms.library.database.beans.MtrcTyp" fetch="select">
<column name="SUPER_MTRC_TYP_ID">
<comment></comment>
</column>
</many-to-one>
-->
<property name="mtrcTypNme" type="string">
<column name="MTRC_TYP_NME" length="50" not-null="true" unique="true">
<comment></comment>
</column>
</property>
<property name="mtrcTypDsc" type="string">
<column name="MTRC_TYP_DSC" length="254" not-null="true">
<comment></comment>
</column>
</property>
<property name="cratUserId" type="string">
<column name="CRAT_USER_ID" length="8" not-null="true">
<comment></comment>
</column>
</property>
<property name="cratTsp" type="timestamp">
<column name="CRAT_TSP" length="26" not-null="true">
<comment></comment>
</column>
</property>
<property name="updUserId" type="string">
<column name="UPD_USER_ID" length="8" not-null="true">
<comment></comment>
</column>
</property>
<property name="updTsp" type="timestamp">
<column name="UPD_TSP" length="26" not-null="true">
<comment></comment>
</column>
</property>
<set name="mtrcTyps" inverse="true">
<key>
<column name="SUPER_MTRC_TYP_ID">
<comment></comment>
</column>
</key>
<one-to-many class="com.transunion.ms.library.database.beans.MtrcTyp" />
</set>
<set name="bfsVrsnMtrcs" inverse="true">
<key>
<column name="MTRC_TYP_ID" not-null="true">
<comment></comment>
</column>
</key>
<one-to-many class="com.transunion.ms.library.database.beans.BfsVrsnMtrc" />
</set>
</class>
</hibernate-mapping>

Code between sessionFactory.openSession() and session.close():
Call this function with key equal to a valid value within the database, in this case "RECORDS_IN".

public MtrcTyp findByKey( String key )
{
MtrcTyp keyValue = null;

Criteria crit = HibernateUtil_s.currentSession()
.createCriteria( MtrcTyp.class);

crit.add( Restrictions.eq( "mtrcTypNme", key ) );

List< MtrcTyp > results = crit.list();
if ( results.size() == 1 )
{
keyValue = results.get( 0 );
}



return keyValue;
}

Full stack trace of any exception that occurs:

Name and version of the database you are using:
DB2

The generated SQL (show_sql=true):
select this_.MTRC_TYP_ID as MTRC1_2_0_, this_.DATA_TYP_ID as DATA2_2_0_, this_.MTRC_TYP_NME as MTRC3_2_0_, this_.MTRC_TYP_DSC as MTRC4_2_0_, this_.CRAT_USER_ID as CRAT5_2_0_, this_.CRAT_TSP as CRAT6_2_0_, this_.UPD_USER_ID as UPD7_2_0_, this_.UPD_TSP as UPD8_2_0_ from TRG2DEVL.MTRC_TYP this_ where this_.MTRC_TYP_NME=?
Hibernate: select this_.MTRC_TYP_ID as MTRC1_2_0_, this_.DATA_TYP_ID as DATA2_2_0_, this_.MTRC_TYP_NME as MTRC3_2_0_, this_.MTRC_TYP_DSC as MTRC4_2_0_, this_.CRAT_USER_ID as CRAT5_2_0_, this_.CRAT_TSP as CRAT6_2_0_, this_.UPD_USER_ID as UPD7_2_0_, this_.UPD_TSP as UPD8_2_0_ from TRG2DEVL.MTRC_TYP this_ where this_.MTRC_TYP_NME=?

Debug level Hibernate log excerpt:
28375 [main] INFO main - A Hibernate session is created.
28375 [main] DEBUG org.hibernate.transaction.JDBCTransaction - begin
28375 [main] DEBUG org.hibernate.jdbc.ConnectionManager - opening JDBC connection
28375 [main] DEBUG org.hibernate.transaction.JDBCTransaction - current autocommit status: false
41406 [main] INFO main - A Hibernate session is created.
42265 [main] DEBUG org.hibernate.jdbc.AbstractBatcher - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
42265 [main] DEBUG org.hibernate.SQL - select this_.MTRC_TYP_ID as MTRC1_2_0_, this_.DATA_TYP_ID as DATA2_2_0_, this_.MTRC_TYP_NME as MTRC3_2_0_, this_.MTRC_TYP_DSC as MTRC4_2_0_, this_.CRAT_USER_ID as CRAT5_2_0_, this_.CRAT_TSP as CRAT6_2_0_, this_.UPD_USER_ID as UPD7_2_0_, this_.UPD_TSP as UPD8_2_0_ from TRG2DEVL.MTRC_TYP this_ where this_.MTRC_TYP_NME=?
Hibernate: select this_.MTRC_TYP_ID as MTRC1_2_0_, this_.DATA_TYP_ID as DATA2_2_0_, this_.MTRC_TYP_NME as MTRC3_2_0_, this_.MTRC_TYP_DSC as MTRC4_2_0_, this_.CRAT_USER_ID as CRAT5_2_0_, this_.CRAT_TSP as CRAT6_2_0_, this_.UPD_USER_ID as UPD7_2_0_, this_.UPD_TSP as UPD8_2_0_ from TRG2DEVL.MTRC_TYP this_ where this_.MTRC_TYP_NME=?
43890 [main] DEBUG org.hibernate.jdbc.AbstractBatcher - about to open ResultSet (open ResultSets: 0, globally: 0)
44015 [main] DEBUG org.hibernate.loader.Loader - result row: EntityKey[com.transunion.ms.library.database.beans.MtrcTyp#1]
44578 [main] DEBUG org.hibernate.jdbc.AbstractBatcher - about to close ResultSet (open ResultSets: 1, globally: 1)
44656 [main] DEBUG org.hibernate.jdbc.AbstractBatcher - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
44703 [main] DEBUG org.hibernate.engine.TwoPhaseLoad - resolving associations for [com.transunion.ms.library.database.beans.MtrcTyp#1]
44719 [main] ERROR main - java.lang.NullPointerException
44719 [main] DEBUG org.hibernate.transaction.JDBCTransaction - rollback
44765 [main] DEBUG org.hibernate.transaction.JDBCTransaction - rolled back JDBC Connection
44765 [main] DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
44765 [main] DEBUG org.hibernate.jdbc.ConnectionManager - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]


Problems with Session and transaction handling?

Read this: http://hibernate.org/42.html