UnsupportedOperationException: null

java.lang.UnsupportedOperationException: null
    at java.util.AbstractList.add(AbstractList.java:148)
    at java.util.AbstractList.add(AbstractList.java:108)
    at org.kuali.rice.kns.lookup.AbstractLookupableHelperServiceImpl.performLookup(AbstractLookupableHelperServiceImpl.java:1141)
    at org.kuali.rice.kns.lookup.KualiLookupableImpl.performLookup(KualiLookupableImpl.java:307)
    at za.org.kuali.rice.krad.dao.impl.LookupDaoOjbOverrideTest.countResultRows(LookupDaoOjbOverrideTest.java:129)
    at za.org.kuali.rice.krad.dao.impl.LookupDaoOjbOverrideTest.testLookup_vendor(LookupDaoOjbOverrideTest.java:109)