Problem in type casting an oracle connection

Issue

• We have a problem when trying to cast a connection using the following code:

@Resource(name="java:jboss/datasources/jdbc/testDS")
     private DataSource ds;

public String getTest(Integer chiave) throws TestException {
         String test = null;
         String query = "SELECT a FROM test_table WHERE
b = ?";
         try {

             Connection conn = ds.getConnection();
             WrappedConnection wc = (WrappedConnection) conn;
             OracleConnection oc =
(OracleConnection)wc.getUnderlyingConnection();
             OraclePreparedStatement ops =
(OraclePreparedStatement)oc.prepareStatement(query);
             ops.setInt(1, test);
             ResultSet rset = ops.executeQuery();
             OracleResultSet orset =
(OracleResultSet)rset.unwrap(OracleResultSet.class);
                while (orset.next()) {
                    XMLType xml =
XMLType.createXML(orset.getOPAQUE("test"));
                    if (xml != null) {
                     xbrl = xml.getStringVal();
                     logger.debug("test=" + test);
                 }
                }
                conn.close();
             return test;
         }
         catch(Exception e) {
             logger.error(e.getMessage(),e);
             throw new
TestException(ExceptionErrorKey.111,Messages.getString(ExceptionErrorKey.111.name()));
         }

     }

• In jboss deployment-structure we include the dependency to the module: org.jboss.ironjacamar.jdbcadapters.Have you any idea?