Java – Null Pointer when populating Grails Domain object with Oracle 10g long field

We are trying to populate a domain object from an oracle 10g database. The field in question is defined as a string in the domain object with the following constraints.

zdata(blank:false,maxSize:3000000)

The size of the data is approximately 70K of XML.

The table definition looks like this:

ZDATA NOT NULL LONG()

We are using the grails generated getter to access the table:

reportData = ReportData.get(reportDataId)

When making this call we are getting a null pointer exception. Here is a portion of our stack trace.
java.lang.NullPointerException
at java.lang.String.(String.java:176)
at oracle.sql.CharacterSet.AL32UTF8ToString(CharacterSet.java:1518)
at oracle.jdbc.driver.DBConversion.CharBytesToString(DBConversion.java:610)
at oracle.jdbc.driver.DBConversion.CharBytesToString(DBConversion.java:555)
at oracle.jdbc.driver.LongAccessor.getString(LongAccessor.java:217)
at oracle.jdbc.driver.T4CLongAccessor.getString(T4CLongAccessor.java:426)
at oracle.jdbc.driver.OracleResultSetImpl.getString(OracleResultSetImpl.java:403)
at oracle.jdbc.driver.OracleResultSet.getString(OracleResultSet.java:1515)
at org.apache.commons.dbcp.DelegatingResultSet.getString(DelegatingResultSet.java:224)
at org.hibernate.type.StringType.get(StringType.java:18)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:163)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:154)
at org.hibernate.loader.hql.QueryLoader.getResultColumnOrRow(QueryLoader.java:333)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:606)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.doList(Loader.java:2220)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
at org.hibernate.loader.Loader.list(Loader.java:2099)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:378)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:338)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1121)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at org.codehaus.groovy.grails.orm.hibernate.metaclass.ExecuteQueryPersistentMethod$1.doInHibernate(ExecuteQueryPersistentMethod.java:94)

we are using oracle driver 10.2.0.3.0.