import com.apple.laf.ScreenMenuBar; //导入依赖的package包/类
@SuppressWarnings("deprecation")
static void installDefaultMenuBar(final JMenuBar menuBar) {
    if (menuBar == null) {
        // intentionally clearing the default menu
        nativeSetDefaultMenuBar(0);
        return;
    }

    final MenuBarUI ui = menuBar.getUI();
    if (!(ui instanceof AquaMenuBarUI)) {
        // Aqua was not installed
        throw new IllegalStateException("Application.setDefaultMenuBar() only works with the Aqua Look and Feel");
    }

    final AquaMenuBarUI aquaUI = (AquaMenuBarUI)ui;
    final ScreenMenuBar screenMenuBar = aquaUI.getScreenMenuBar();
    if (screenMenuBar == null) {
        // Aqua is installed, but we aren't using the screen menu bar
        throw new IllegalStateException("Application.setDefaultMenuBar() only works if apple.laf.useScreenMenuBar=true");
    }

    screenMenuBar.addNotify();
    final MenuComponentPeer peer = screenMenuBar.getPeer();
    if (!(peer instanceof CMenuBar)) {
        // such a thing should not be possible
        throw new IllegalStateException("Unable to determine native menu bar from provided JMenuBar");
    }

    // grab the pointer to the CMenuBar, and retain it in native
    nativeSetDefaultMenuBar(((CMenuBar)peer).getModel());
}
 

import com.apple.laf.ScreenMenuBar; //导入依赖的package包/类
@SuppressWarnings("deprecation")
static void installDefaultMenuBar(final JMenuBar menuBar) {
    if (menuBar == null) {
        // intentionally clearing the default menu
        nativeSetDefaultMenuBar(0);
        return;
    }

    final MenuBarUI ui = menuBar.getUI();
    if (!(ui instanceof AquaMenuBarUI)) {
        // Aqua was not installed
        throw new IllegalStateException("Application.setDefaultMenuBar() only works with the Aqua Look and Feel");
    }

    final AquaMenuBarUI aquaUI = (AquaMenuBarUI)ui;
    final ScreenMenuBar screenMenuBar = aquaUI.getScreenMenuBar();
    if (screenMenuBar == null) {
        // Aqua is installed, but we aren't using the screen menu bar
        throw new IllegalStateException("Application.setDefaultMenuBar() only works if apple.laf.useScreenMenuBar=true");
    }

    screenMenuBar.addNotify();
    final MenuComponentPeer peer = screenMenuBar.getPeer();
    if (!(peer instanceof CMenuBar)) {
        // such a thing should not be possible
        throw new IllegalStateException("Unable to determine native menu bar from provided JMenuBar");
    }

    // grab the pointer to the CMenuBar, and retain it in native
    ((CMenuBar) peer).execute(_AppMenuBarHandler::nativeSetDefaultMenuBar);
}
 

import com.apple.laf.ScreenMenuBar; //导入依赖的package包/类
static void installDefaultMenuBar(final JMenuBar menuBar) {
    if (menuBar == null) {
        // intentionally clearing the default menu
        nativeSetDefaultMenuBar(0);
        return;
    }

    final MenuBarUI ui = menuBar.getUI();
    if (!(ui instanceof AquaMenuBarUI)) {
        // Aqua was not installed
        throw new IllegalStateException("Application.setDefaultMenuBar() only works with the Aqua Look and Feel");
    }

    final AquaMenuBarUI aquaUI = (AquaMenuBarUI)ui;
    final ScreenMenuBar screenMenuBar = aquaUI.getScreenMenuBar();
    if (screenMenuBar == null) {
        // Aqua is installed, but we aren't using the screen menu bar
        throw new IllegalStateException("Application.setDefaultMenuBar() only works if apple.laf.useScreenMenuBar=true");
    }

    screenMenuBar.addNotify();
    final Object peer = AWTAccessor.getMenuComponentAccessor().getPeer(screenMenuBar);
    if (!(peer instanceof CMenuBar)) {
        // such a thing should not be possible
        throw new IllegalStateException("Unable to determine native menu bar from provided JMenuBar");
    }

    // grab the pointer to the CMenuBar, and retain it in native
    nativeSetDefaultMenuBar(((CMenuBar)peer).getModel());
}