EventHandler<T extends Event> in JavaFX a class or interface.

[Gaurav Pruthi]

Hi,

I have picked a basic example of printing "Hello World" on screen when the mouse is clicked The code goes like this.

package sample;
 
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
 
/**
 *
 * @author gauravp
 */
public class Sample extends Application {
 
    /**
     * @param args the command line arguments
     */
    Button btn = new Button("ok");
    //Label l = new Label("Done");
 
    public static void main(String[] args) {
        launch(args);
    }
 
    @Override
    public void start(Stage primaryStage) {
 
        primaryStage.setTitle("First Stage");
 
 
        //Created anonymous inner class EventHandler<ActionEvent>
        btn.setOnAction(new EventHandler<ActionEvent>() {
 
            @Override
            public void handle(ActionEvent event) {
 
                    System.out.print("Hello World !!");
 
 
            }
        });
 
        StackPane root = new StackPane();
        root.getChildren().add(btn);
        primaryStage.setScene(new Scene(root, 300, 250));
        primaryStage.show();
    }
}
 

In documentation it is mentioned that EventHandler is an interface , but how come the interface be instantiated...

"new EventHandler<ActionEvent>()"

In a lot of confusion....please reply if you have any idea.. Here is the link

http://docs.oracle.com/javafx/2.0/api/javafx/event/EventHandler.html