Question

I am looking if it is possible to add an item (“about” the application) in the Winwdows system menu of the current JFrame.

As it is suggested in that answer, I know that it could be possible to tweak the menu via JNI/JNA and the windows API with GetSystemMenu(), but I am looking if it is possible in plain vanilla Java/Swing.

I have found something telling it should be possible in that forum thread:

this prior to creating a JFrame

JFrame.setDefaultLookAndFeelDecorated(true);

then, before adding anything to the frame, iterate the frame’s components,
looking for the JMenu. When found, add your ‘about’ menuItem

just tested, works fine.

Alas, a whole sscce is not provided, and I did not manage to make it work in my code. When breakpointing just after the windows creation prior adding the components, I see no JMenu. Neither at the first level (JRootPane) nor in the successively embedded components (JPanel, JLayeredPane).

If it matters, I am dealing with Java 6/7 on WinXP and Win7, the window is created as a new JFrame("some title") and I am using the native look & feel UIManager.getSystemLookAndFeelClassName().

Answer 1

The JMenu component does exist when using the cross-platform look and feel. The hierarchy of components is:

class Test
  class javax.swing.JRootPane
    class javax.swing.JPanel
    class javax.swing.JLayeredPane
      class javax.swing.JPanel
      class javax.swing.plaf.metal.MetalTitlePane
        class javax.swing.plaf.metal.MetalTitlePane$SystemMenuBar
          class javax.swing.JMenu
        class javax.swing.JButton
        class javax.swing.JButton
        class javax.swing.JButton

Unfortunately, when using the Windows look and feel, Java doesn’t know about the title bar at all. You’re probably stuck either using JNA or a different laf.