private ListBox getScheme() { scheme = new ListBox(); scheme.addItem("--Select--", "--None--"); for (String[] item : initData.getScheme()) { scheme.addItem(item[1], item[1]); } scheme.setWidth("100%"); scheme.addChangeHandler( new ChangeHandler() { public void onChange(ChangeEvent event) { if (!scheme.getValue((scheme.getSelectedIndex())).equals("") && !scheme.getValue(scheme.getSelectedIndex()).equals("--None--")) { exp.setSchemeURI(scheme.getValue(scheme.getSelectedIndex())); } else { exp.setSchemeURI(null); } } }); return scheme; }