CriteriaBuilder equal operator does not work - jpa

Question

I am new to JPA. I am using EclipseLink 2.5.2 against Oracle database with Oracle JDBC driver. For the simple code below:
public List<DummyGrp> findByProperty(String propertyName, Object value) {
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<DummyGrp> cq = cb.createQuery(DummyGrp.class);
Root<DummyGrp> rootQuery = cq.from(DummyGrp.class);
cq.select(rootQuery);
cq.where(cb.equal(rootQuery.get(propertyName),value));
TypedQuery<DummyGrp> q = entityManager.createQuery(cq);
return q.getResultList();
}
The result is always empty. After turning on debug, I did see the SQL:
[EL Fine]: sql: 2015-01-09 12:20:51.215--ClientSession(559179052)--Connection(1008188683)--Thread(Thread[main,5,main])--SELECT ID, DATA_TYPE_IND, ENTRY_TYPE_IND, GRP_DESC, GRP_NAME, TRANS_ORIG_MM, TRANS_ORIG_YR FROM DUMMY_GRP WHERE (GRP_NAME = ?)
bind => [TG_dabfe8]
I debugged the Oracle JDBC. I was able to debug JDBC to the point that I can see the client side Oracle Statement with bind parameter and if I run the statement directly from an IDE, I can get result expected.
If I change the "equal" operator to "like" (see below):
cq.where(cb.like(rootQuery.get(propertyName),value+"%"));
I get result back.
I am sure I might be missing something simple. Can anyone enlighten me?
Thanks in advance,
Peter C.
By the way, here is the Oracle JDBC Diagnositcs log:
CONFIG: 5E158F33 SQL: SELECT ID, DATA_TYPE_IND, ENTRY_TYPE_IND, GRP_DESC, GRP_NAME, TRANS_ORIG_MM, TRANS_ORIG_YR FROM DUMMY_GRP WHERE (GRP_NAME = ?)
java.lang.Throwable: No Error
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1647)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:4401)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:4482)
at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeQuery(OraclePreparedStatementWrapper.java:6272)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeSelect(DatabaseAccessor.java:1007)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:642)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:558)
at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall(AbstractSession.java:2002)
at org.eclipse.persistence.sessions.server.ClientSession.executeCall(ClientSession.java:298)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:242)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:228)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeSelectCall(DatasourceCallQueryMechanism.java:299)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.selectAllRows(DatasourceCallQueryMechanism.java:694)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRowsFromTable(ExpressionQueryMechanism.java:2738)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRows(ExpressionQueryMechanism.java:2691)
at org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:495)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1168)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:899)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1127)
at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:403)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1215)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2896)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1804)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1786)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1751)
at org.eclipse.persistence.internal.jpa.QueryImpl.executeReadQuery(QueryImpl.java:258)
at org.eclipse.persistence.internal.jpa.QueryImpl.getResultList(QueryImpl.java:469)
at com.gaig.plentry.dao.DummyGroupDAOImpl.findByProperty(DummyGroupDAOImpl.java:47)
at com.gaig.plentry.dao.DummyGroupDAOImpl.findByGroupName(DummyGroupDAOImpl.java:28)
at com.gaig.plentry.dao.DummyGroupDAOImpl$$FastClassBySpringCGLIB$$2d2bc23e.invoke()
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:267)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)