Setting icon with javaFX does not show in task list

I try to set an icon (*.png) with javaFX, but it does not show in the task bar, instead I see the default icon (white cogwheel on light gray background).

Here is my code:

package application;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

// copied and adapted from https://codemia.io/knowledge-hub/path/javafx_application_icon
//
// java -version
// openjdk version "21.0.8" 2025-07-15
// OpenJDK Runtime Environment (build 21.0.8+9-Ubuntu-0ubuntu124.04.1)
// OpenJDK 64-Bit Server VM (build 21.0.8+9-Ubuntu-0ubuntu124.04.1, mixed mode, sharing)
//
// lsb_release -a
// No LSB modules are available.
// Distributor ID:	Ubuntu
// Description:	Ubuntu 24.04.3 LTS
// Release:	24.04
// Codename:	noble

public class IconTest extends Application {

	// manually checked that the file can be displayed and the image has 48x48 pixels
	String pathname = "/home/watchmaker/playground/I48.png";

	@Override
	public void start(Stage stage) throws FileNotFoundException {
		// Create a layout
		StackPane root = new StackPane();
		Scene scene = new Scene(root, 400, 300);

		File ifi = new File(pathname);
		// just in case something's wrong at runtime
		System.out.println("File=" + ifi.getAbsolutePath() + " is readable=" + ifi.canRead());
		Image icon = new Image(new FileInputStream(ifi));
		stage.getIcons().add(icon);

		stage.setTitle("Try and cry");
		stage.setScene(scene);
		stage.show();
	}

	public static void main(String[] args) {
		launch(args);
	}
}

What is wrong?

posted about 1 month ago

CC BY-SA 4.0

watchmaker‭

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