[Demonstration 1]

[Buggy Method]
@EventHandler(priority = EventPriority.HIGH)
public void messageLogin(PlayerJoinEvent event) {
    MPlayer player = MPlayer.get(event.getPlayer());
    event.getPlayer().setAllowFlight(true);
    if (player.getRace() == null) {
        player.setRace(MRaceColl.get().get(MConf.get().getDefaultRace()));
    }
    if (player.getRace().getId().equalsIgnoreCase(MConf.get().getDefaultRace()))
        return;
    MRace race = player.getRace();
    player.message(Txt.parse("<i>You are currently a(n) <pink>" + race.getName() + "<i>."));
}

[Buggy Hunk]
event.getPlayer().setAllowFlight(true);

[Patch]
if (!player.getPlayer().getAllowFlight()) player.getPlayer().setAllowFlight(true);

[Demonstration 2]

[Buggy Method]
private void setupDragDropHandlers() {
    this.setOnDragOver(new EventHandler<DragEvent>() {

        @Override
        public void handle(DragEvent event) {
            if (event.getGestureSource() != this) {
                event.acceptTransferModes(TransferMode.COPY);
            }
            event.consume();
        }
    });
    this.setOnDragDropped(event -> {
        Dragboard dragboard = event.getDragboard();
        boolean success = false;
        if (dragboard.hasString()) {
            DiagramItem item = PaletteItemRegistry.getItem(dragboard.getString());
            if (item != null) {
                item.relocate(event.getX(), event.getY());
                Command addCommand = new AddItemsCommand(this, Arrays.asList(item));
                ChangeManager.getInstance().putCommand(addCommand);
                addCommand.execute();
                success = true;
            }
        }
        event.setDropCompleted(success);
        event.consume();
    });
}

[Buggy Hunk]
Command addCommand = new AddItemsCommand(this, Arrays.asList(item));

[Patch]
Command addCommand = new AddItemsCommand(this, Collections.singletonList(item));

[Demonstration 3]

[Buggy Method]
public void setAdapter(ExpandableListAdapter adapter) {
    super.setAdapter(adapter);
    // Make sure that the adapter extends AnimatedExpandableListAdapter
    if (adapter instanceof AnimatedExpandableListAdapter) {
        this.adapter = (AnimatedExpandableListAdapter) adapter;
        this.adapter.setParent(this);
    } else {
        throw new ClassCastException(adapter.toString() + " must implement AnimatedExpandableListAdapter");
    }
}

[Buggy Hunk]
throw new ClassCastException(adapter.toString() + " must implement AnimatedExpandableListAdapter");

[Patch]
throw new ClassCastException(adapter + " must implement AnimatedExpandableListAdapter");