class SwingThreadFrame extends JFrame {
	public SwingThreadFrame() {
		setTitle("Swing Thread");
		
		final JComboBox<Integer> combo = new JComboBox<Integer>();
		combo.insertItemAt(Integer.MAX_VALUE,0);
		combo.setPrototypeDisplayValue(combo.getItemAt(0));
		combo.setSelectedIndex(0);
		
		JPanel panel = new JPanel();
		
		JButton goodButton = new JButton("Good");
		goodButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent event) {
				new Thread(new GoodWorkerRunnable(combo)).start();
			}
		});
		panel.add(goodButton);
		
		JButton badButton = new JButton("Bad");
		badButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent event) {
				new Thread(new BadWorkerRunnable(combo)).start();
			}
		});
		panel.add(badButton);
		
		panel.add(combo);
		add(panel);
		pack();
	}
}

class GoodWorkerRunnable implements Runnable {

	public GoodWorkerRunnable(JComboBox<Integer> combo) {
		this.combo = combo;
		generator = new Random();
	}
	
	@Override
	public void run() {
		try {
			while(true) {
				EventQueue.invokeLater(new Runnable() {
					@Override
					public void run() {
						int i = Math.abs(generator.nextInt());
						if(i % 2 == 0) {
							combo.insertItemAt(i,0);
						} else if(combo.getItemCount() > 0) {
							combo.removeItemAt(i % combo.getItemCount());
						}
					}
				});
				
				Thread.sleep(1);
			}
		} catch (InterruptedException e) {
		}
		
	}
	
	private JComboBox<Integer> combo;
	private Random generator;
}
class BadWorkerRunnable implements Runnable {

	public BadWorkerRunnable(JComboBox<Integer> combo) {
		this.combo = combo;
		generator = new Random();
	}
	
	@Override
	public void run() {
		try {
			while(true) {
				int i = Math.abs(generator.nextInt());
				if(i % 2 == 0) {
					combo.insertItemAt(i,0);
				} else if(combo.getItemCount() > 0) {
					combo.removeItemAt(i % combo.getItemCount());
				}
				
				Thread.sleep(1);
			}
		} catch (InterruptedException e) {
		}
		
	}
	
	private JComboBox<Integer> combo;
	private Random generator;
}