could not cast dbcp objects created using tomcat JNDI

[pqin]

I retrieved an object of DataSource using Tomcat's JNDI simulation. It is an
instance of BasicDataSource. I tried to cast it to BasicDataSource and got a
ClassCastException.
 
Context ctx = new InitialContext() ;
Context envCtx = (Context) ctx.lookup("java:comp/env") ;
DataSource ds = (DataSource) envCtx.lookup("jdbc/myoracle") ;
BasicDataSource basic = (BasicDataSource) ds ;
 
Actually, I cannot cast any DBCP objects, e.g. PoolableConnection.