void buildGui() {
		JMenuBar menuBar = new JMenuBar();
		JMenu menu = new JMenu("File");
		menuBar.add(menu);
		openItem = new JMenuItem("Open Database...");
		menu.add(openItem);
		openItem.addActionListener(e -> openDb());
		closeItem = new JMenuItem("Close Database");
		menu.add(closeItem);
		closeItem.setEnabled(false);
		closeItem.addActionListener(e -> closeDb());
		JMenuItem exitItem = new JMenuItem("Exit");
		menu.add(exitItem);
		exitItem.addActionListener(e -> System.exit(0));
		setJMenuBar(menuBar);
	}
<code>DbViewer</code> is a diagnostic application for viewing a
Ghidra database.
Ghidra/Features/DebugUtils/src/main/java/db/DbViewer.java