Warning message not displaying - mysql

Question

Take a look at the code below.
void viewStudent() throws ClassNotFoundException, SQLException {
try {
Class.forName("com.mysql.jdbc.Driver");
connect2 = DriverManager
.getConnection("jdbc:mysql://localhost:3306/project?"
+ "user=root&password=virus");
statement2 = connect2.createStatement();
preparedStatement2 = connect2
.prepareStatement("select regno from student where regno= "
+ ""+Integer.parseInt(txt1.getText())+"");
resultSet2 = preparedStatement2.executeQuery();
checkRegno(resultSet2);
} catch (ClassNotFoundException | SQLException e) {
throw e;
} finally {
close1();
}
}
void checkRegno(ResultSet resultSet2) throws SQLException {
while (resultSet2.next()) {
int trno = Integer.parseInt(resultSet2.getString("regno"));
int regno = Integer.parseInt(txt1.getText());
if (trno == regno) {
resultSet2 = statement2
.executeQuery("select * from student where regno= " + regno + "");
writeResultSet(resultSet2);
}
else {
final Text warning = new Text("Register Number Not Found...!");
warning.setFill(Color.RED);
warning.setStyle("-fx-font: 18 arial;");
Stage dialogStage = new Stage();
dialogStage.setTitle("Warning");
dialogStage.initStyle(StageStyle.UTILITY);
dialogStage.setScene(new Scene(VBoxBuilder.create().
children(warning).alignment(Pos.CENTER).
padding(new Insets(25, 25, 25, 25)).build()));
dialogStage.show();
}
}
}
I have a table named 'student' in database. When the "if (trno == regno)" is true, the "writeResultSet(resultSet2);" is working fine. When it is false, the else part is not working. How can I solve this issue ?

Answer 1

Most probably you are not calling your UI code on the FX thread. Try next:
Platform.runLater(new Runnable() {
#Override
public void run() {
final Text warning = new Text("Register Number Not Found...!");
warning.setFill(Color.RED);
warning.setStyle("-fx-font: 18 arial;");
Stage dialogStage = new Stage();
dialogStage.setTitle("Warning");
dialogStage.initStyle(StageStyle.UTILITY);
dialogStage.setScene(new Scene(VBoxBuilder.create().
children(warning).alignment(Pos.CENTER).
padding(new Insets(25, 25, 25, 25)).build()));
dialogStage.show();
}
});