Java Database Connectivity (JDBC)

I have the following code written in java in a unix box and this is the error I get when compiling the code. I am not able to find which specific jar or class file I need, Kindly help.

XMLHelper.java:0: Class oracle.sql.OPAQUE not found in class oracle.xdb.XMLType.
/**
^
1 error

OracleResultSet orst = .... some code to get data
orst.next();
//either of the following 2 lines give the same error
//XMLType dXml = XMLType.createXML(orst.getOPAQUE(1)) ;
XMLType dXml = (XMLType)orst.getObject(i);
xmlDoc = dXml.getDOM();

Please help