The following works:
String hql = "select new map(log as log, cur as cur) " +
" from db2.co99blh.Dtnamelog log, " +
" db2.co99blh.Dtname cur " +
" where " +
" (log.id.mlid = cur.id.mid and " +
" log.id.mlgroup = cur.id.mgroup) " +
" order by log.mlco";

But when I try to change the above to use a left join.
nullorg.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:44) org.hibernate.persister.entity.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:38) org.hibernate.persister.entity.AbstractEntityPersister.toType(AbstractEntityPersister.java:1358) org.hibernate.loader.criteria.CriteriaQueryTranslator.getPathEntityName(CriteriaQueryTranslator.java:204) org.hibernate.loader.criteria.CriteriaQueryTranslator.createCriteriaEntityNameMap(CriteriaQueryTranslator.java:191) org.hibernate.loader.criteria.CriteriaQueryTranslator.<init>(CriteriaQueryTranslator.java:81) org.hibernate.loader.criteria.CriteriaLoader.<init>(CriteriaLoader.java:58) org.hibernate.impl.SessionImpl.list(SessionImpl.java:1550) org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283) utilities.ListChangedCompanyNames2.query(ListChangedCompanyNames2.java:82)

Right now I was trying with a Criteria, so here is the code from that:
Criteria crit = session.createCriteria("db2.co99blh.Dtnamelog", "log");
crit.createAlias("Dtname", "cur", Criteria.LEFT_JOIN);
crit.add(Restrictions.eqProperty("log.id.mlid", "cur.id.mid"));
crit.add(Restrictions.eqProperty("log.id.mlgroup", "cur.id.mgroup"));
crit.setMaxResults(resultsPerPage);
crit.setFirstResult(startRecord);
list = crit.list(); //Exception thrown here (ListChangedCompanyNames2.java:82)

I've seen some reference that I might need to do something in the mapping files to enable left joins... I have no idea, as long as I don't use joins everything works fine, but in this case I definitely need all the elements in the left table and generating a cross product bothers me.

I don't know why I have such issues with joins and hibernate, is there a tutorial someone can recommend for this issue?

Perhaps using a mysql db (I am using DB2 but anything is better than nothing) and describing the process from table mapping to using the join? Even better start with table creation in mysql, then table mapping, and then using the join... That would be really ideal.

Okay I obviously don't know what I'm doing if I can't get a join working...

What is the best hibernate reference out there right now?
What is the best hibernate tutorial out there?