public void actionPerformed(ActionEvent e){
  if (e.getActionCommand() == "OnlyReceipt") {
    if (fcheckReceipt.isSelected())     fcheckPayment.setSelected(false);
  }
  if (e.getActionCommand() == "OnlyPayment") {
    if (fcheckPayment.isSelected())     fcheckReceipt.setSelected(false);
  }
  super.actionPerformed(e);
}

public void actionPerformed ( ActionEvent e ) { if ( e . getActionCommand ( ) == "OnlyReceipt" ) { if ( fcheckReceipt . isSelected ( ) ) fcheckPayment . setSelected ( false ) ; } if ( e . getActionCommand ( ) == "OnlyPayment" ) { if ( fcheckPayment . isSelected ( ) ) fcheckReceipt . setSelected ( false ) ; } super . actionPerformed ( e ) ; }
( button ) action listener & popup menu
