Desktop class problem

Question

The code below does nothing. No file opened, no exception thrown, no output.
What can I do to discover the problem?
It does indeed execute the desktop.open(file) line.
Using JDK 1.16.0_81
File file = new File(pathAndFileString); // an existing text file
if (Desktop.isDesktopSupported()) {
     Desktop desktop = Desktop.getDesktop();
     if (desktop.isSupported(Desktop.Action.OPEN )) {
          try {
               desktop.open(file);
          } catch (IOException e1) {
               e1.printStackTrace();
     else {
          System.out.println("Desktop.Action.OPEN not supported");
else {
     System.out.println("Desktop not supported");
}

Answer 1

package desktopdemo;
import java.awt.Desktop;
import java.io.File;
import java.io.IOException;
public class MyDesktopDemo {
     public MyDesktopDemo() {
          // have tried .txt, .rtf, .pptx all with no effect
          String pathAndFileString = "C:\\my.pptx";
          File file = new File(pathAndFileString);
          if (Desktop.isDesktopSupported()) {
               Desktop desktop = Desktop.getDesktop();
               if (desktop.isSupported(Desktop.Action.OPEN )) {
                    try {
                         System.out.println("desktop.open(" + pathAndFileString + ")"); // gets here
                         desktop.open(file); // but nothing happens
                    } catch (IOException e1) {
                         e1.printStackTrace();
               else {
                    System.out.println("Desktop.Action.OPEN not supported");
          else {
               System.out.println("Desktop not supported");
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new MyDesktopDemo();
}