[Demonstration 1]

[Buggy Method]
@PostConstruct
public void init() {
    String articleId = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("articleId");
    if (null == articleId) {
        LOGGER.error("Review called with empty article ID");
    } else {
        Long articleIdAsLong = Long.parseLong(articleId);
        selectedArticle = articleService.find(articleIdAsLong);
        if (null == selectedArticle) {
            LOGGER.error("Failed to load article with id " + articleId);
        }
    }
    for (String category : categoryService.getCategories()) {
        availableCategories.put(category, category);
    }
}

[Buggy Hunk]
String articleId = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("articleId");

[Patch]
String articleId = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get(JSFConstants.PARAM_NAME_ARTICLE_ID);

[Demonstration 2]

[Buggy Method]
@Override
public boolean apply(Game game, Ability source) {
    Player controller = game.getPlayer(source.getControllerId());
    if (controller == null) {
        return false;
    }
    StackObject spell = null;
    for (StackObject object : game.getStack()) {
        if (object instanceof Spell && object.getSourceId().equals(source.getSourceId())) {
            spell = object;
        }
    }
    if (spell != null) {
        boolean destroyCreatures = true;
        for (UUID playerId : game.getState().getPlayersInRange(controller.getId(), game)) {
            Player player = game.getPlayer(uuid);
            if (player != null && player.chooseUse(Outcome.Detriment, "Have " + spell.getLogName() + " deal 6 damage to you?", game)) {
                destroyCreatures = false;
                player.damage(6, source.getSourceId(), game, false, true);
                game.informPlayers(player.getLogName() + " has " + spell.getName() + " deal 6 to him or her");
            }
        }
        if (destroyCreatures) {
            for (Permanent permanent : game.getBattlefield().getActivePermanents(new FilterCreaturePermanent("creatures"), source.getControllerId(), source.getSourceId(), game)) {
                permanent.destroy(source.getSourceId(), game, true);
            }
        }
        return destroyCreatures;
    }
    return false;
}

[Buggy Hunk]
Player player = game.getPlayer(uuid);

[Patch]
Player player = game.getPlayer(playerId);

[Demonstration 3]

[Buggy Method]
public boolean addNewCategory(String name) {
    if (categories.containsKey(name) == false) {
        Category category = new Category(name);
        DefaultMutableTreeNode node = new DefaultMutableTreeNode(name);
        categories.put(name, category);
        root.add(node);
        category.setIndex(root.getIndex(node));
        treeModel.reload();
        return true;
    } else {
        return false;
    }
}

[Buggy Hunk]
if (categories.containsKey(name) == false) {

[Patch]
if (categories.get(name) == null) {