code: @SuppressWarnings("unchecked")
      protected <T> T getJDBCImplObject(Class<T> interfaceClass) throws SQLException 
      {
          Object impl = WSJdbcTracer.getImpl(getJDBCImplObject());
  
          return interfaceClass.isInstance(impl) ?
                          (T) impl : 
                          mcf.jdbcDriverSpecVersion >= 40 && ((Wrapper) impl).isWrapperFor(interfaceClass) ?
                                          ((Wrapper) impl).unwrap(interfaceClass) :
                                          null;
      }
docs: Locate the underlying JDBC driver's implementation of the specified interface.
  
  @param interfaceClass the interface.
  
  @return the underlying JDBC driver's implementation of the specified interface,
  or NULL if none is found.
  @throws SQLException if an error occurs locating or unwrapping the implementation.