code: @Override
      public SICoreConnection getSICoreConnection() throws IllegalStateException {
  
          if (connectionClosed) {
              throw new IllegalStateException(NLS.getFormattedMessage(
                                                                      ("ILLEGAL_STATE_CWSJR1086"),
                                                                      new Object[] { "getSICoreConnection" }, null));
          }
          return _coreConnection;
  
      }
docs: Returns the core connection created for, and associated with, this
  connection.
  
  @return the core connection
  @throws IllegalStateException
  if this connection has been closed