JavaFX Application Icon

Assuming your stage is "stage" and the file is on the filesystem:

stage.getIcons().add(new Image("file:icon.png"));

As per the comment below, if it's wrapped in a containing jar you'll need to use the following approach instead:

stage.getIcons().add(new Image(<yourclassname>.class.getResourceAsStream("icon.png")));

I tried this and it totally works. The code is:

stage.getIcons().add(   new Image(      <yourclassname>.class.getResourceAsStream( "icon.png" ))); 

icon.png is under the same folder as the source files.

Full program for starters :) This program sets icon for StackOverflowIcon.

import javafx.application.Application;import javafx.scene.Scene;import javafx.scene.image.Image;import javafx.scene.layout.StackPane;import javafx.stage.Stage;public class StackoverflowIcon extends Application {    @Override    public void start(Stage stage) {        StackPane root = new StackPane();        // set icon        stage.getIcons().add(new Image("/path/to/stackoverflow.jpg"));        stage.setTitle("Wow!! Stackoverflow Icon");        stage.setScene(new Scene(root, 300, 250));        stage.show();    }    public static void main(String[] args) {        launch(args);    }}

Output Screnshot

Updated for JavaFX 8

No need to change the code. It still works fine. Tested and verified in Java 1.8(1.8.0_45). Path can be set to local or remote both are supported.

stage.getIcons().add(new Image("/path/to/javaicon.png"));

OR

stage.getIcons().add(new Image("https://example.com/javaicon.png"));

Hope it helps. Thanks!!