src/main/dev/lh/ui/Endscreen.java

@@ -40,14 +40,6 @@ public class Endscreen extends JDialog {
 			contentPanel.setBorder(new EmptyBorder(5, 5, 5, 5));
 			contentPanel.setLayout(new BorderLayout(0, 0));
 			getContentPane().add(contentPanel, BorderLayout.CENTER);
-			addWindowListener(new java.awt.event.WindowAdapter() {
-
-				@Override
-				public void windowClosing(java.awt.event.WindowEvent windowEvent) {
-					Thread.getAllStackTraces().forEach((thread, stackTraceElement) -> thread.interrupt());
-					System.exit(0);
-				}
-			});
 
 			JButton btnNewButton = new JButton("Play again");
 			btnNewButton.setMnemonic(KeyEvent.VK_ENTER);

src/main/dev/lh/ui/GameWindow.java

@@ -25,6 +25,7 @@ public class GameWindow extends JFrame {
 	private static final long	serialVersionUID	= 1L;
 	private Snake				s					= new Snake(7);
 	private FoodFactory			foodFactory			= FoodFactory.getInstance();
+	private Timer timer;
 
 	/**
 	 * @param title the title of the frame
@@ -84,7 +85,8 @@ public class GameWindow extends JFrame {
 			}
 		});
 
-		Timer timer = new Timer(50,
+		timer = new Timer(
+			50,
 				evt -> { s.nextFrame(); if (System.currentTimeMillis() >= foodFactory.getTimeOfNextFood()) newFood(); repaint(); });
 		timer.start();
 
@@ -107,5 +109,8 @@ public class GameWindow extends JFrame {
 	 *
 	 * @since Snake 1.1
 	 */
-	public void close() { dispose(); }
+	public void close() {
+		timer.stop();
+		dispose();
+	}
 }