I have 2 classes that have a one-to-one relationship. If I remove the relationship from the mapping file, I can retrieve both objects. But if I specify the relationship in the hbm.xml file I get the following exception. Has anyone seen this?

14:51:00:490|DEBUG|org.hibernate.util.JDBCExceptionReporter|could not load an entity: [ownit.value.Tracking#component[loanNumber,settleDate]{loanNumber=1001858421, settleDate=2006-01-03 00:00:00}] [select tracking0_.loanNumber as loanNumber20_0_, tracking0_.settleDate as settleDate20_0_, tracking0_.yield as yield20_0_, tracking0_.gainAAdj as gainAAdj20_0_, tracking0_.gainBAdj as gainBAdj20_0_, tracking0_.gainPerLoan as gainPerL6_20_0_, tracking0_.interestDue as interest7_20_0_, tracking0_.interestPending as interest8_20_0_, tracking0_.priceReduction as priceRed9_20_0_, tracking0_.targetRevenue as targetR10_20_0_, tracking0_.trueUpAmount as trueUpA11_20_0_ from Tracking tracking0_ where tracking0_.loanNumber=? and tracking0_.settleDate=?]
java.sql.SQLException: JZ0NC: wasNull called without a preceding call to get a column.
at com.sybase.jdbc2.jdbc.ErrorMessage.raiseError(ErrorMessage.java:498)
at com.sybase.jdbc2.jdbc.SybResultSet.wasNull(SybResultSet.java:194)
at aot.util.DecimalType.nullSafeGet(DecimalType.java:51)
at org.hibernate.type.CustomType.nullSafeGet(CustomType.java:104)
at org.hibernate.type.AbstractType.hydrate(AbstractType.java:81)
at org.hibernate.persister.entity.AbstractEntityPersister.hydrate(AbstractEntityPersister.java:1899)
at org.hibernate.loader.Loader.loadFromResultSet(Loader.java:1372)
at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1300)
at org.hibernate.loader.Loader.getRow(Loader.java:1197)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:569)
at org.hibernate.loader.Loader.doQuery(Loader.java:689)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1785)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:47)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:41)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2730)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:177)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:87)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:862)
at org.hibernate.impl.SessionImpl.internalLoad(SessionImpl.java:830)
at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:266)
at org.hibernate.type.EntityType.resolve(EntityType.java:303)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:116)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:842)
at org.hibernate.loader.Loader.doQuery(Loader.java:717)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.doList(Loader.java:2145)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
at org.hibernate.loader.Loader.list(Loader.java:2024)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:375)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:308)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:153)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1106)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:749)
at aot.util.TestHibernate.doQueryFunding(TestHibernate.java:216)
at aot.util.TestHibernate.testStoreDomainObjects(TestHibernate.java:879)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at junit.framework.TestCase.runTest(TestCase.java:154)
at junit.framework.TestCase.runBare(TestCase.java:127)
at junit.framework.TestResult$1.protect(TestResult.java:106)
at junit.framework.TestResult.runProtected(TestResult.java:124)
at junit.framework.TestResult.run(TestResult.java:109)
at junit.framework.TestCase.run(TestCase.java:118)
at junit.framework.TestSuite.runTest(TestSuite.java:208)
at junit.framework.TestSuite.run(TestSuite.java:203)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:478)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:344)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)

This is a relationship that needs to be constrained. It is solved - I am just an idiot.