Is it possible to change the application icon using JavaFX, or does it have to be done using Swing?
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!!