How to create an alert in JavaFX?

An alert is a dialog which shows pre-built dialog types. You can create an alert by instantiating the javafx.scene.control.Alert class. This class is a subclass of the Dialog class. You can create required type of dialog bypassing the respective parameter at the time of instantiation as −

Alert alert = new Alert(Alert.AlertType.CONFIRMATION);

Example

The following Example demonstrates the creation of an Alert.

import javafx.application.Application; import javafx.geometry.Insets; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.control.Alert; import javafx.scene.control.Alert.AlertType; import javafx.scene.control.Button; import javafx.scene.control.ButtonBar.ButtonData; import javafx.scene.control.ButtonType; import javafx.scene.control.Dialog; import javafx.scene.layout.HBox; import javafx.stage.Stage; import javafx.scene.paint.Color; import javafx.scene.text.Font; import javafx.scene.text.FontPosture; import javafx.scene.text.FontWeight; import javafx.scene.text.Text; public class AlertExample extends Application {    public void start(Stage stage) {       //Creating a dialog       Alert alert = new Alert(Alert.AlertType.CONFIRMATION);       //Setting the title       alert.setTitle("Alert");       ButtonType type = new ButtonType("Ok", ButtonData.OK_DONE);       //Setting the content of the dialog       alert.setContentText("This is a confirmmation alert");       //Adding buttons to the dialog pane       alert.getDialogPane().getButtonTypes().add(type);       //Setting the label       Text txt = new Text("Click the button to show the dialog");       Font font = Font.font("verdana", FontWeight.BOLD, FontPosture.REGULAR, 12);       txt.setFont(font);       //Creating a button       Button button = new Button("Show Dialog");       //Showing the dialog on clicking the button       button.setOnAction(e -> {          alert.showAndWait();       });       //Creating a vbox to hold the button and the label       HBox pane = new HBox(15);       //Setting the space between the nodes of a HBox pane       pane.setPadding(new Insets(50, 150, 50, 60));       pane.getChildren().addAll(txt, button);       //Creating a scene object       Scene scene = new Scene(new Group(pane), 595, 300, Color.BEIGE);       stage.setTitle("Alert");       stage.setScene(scene);       stage.show();    }    public static void main(String args[]){       launch(args);    } }

Output