[Demonstration 1]

[Buggy Method]
public void addMember(CommandSender sender, String regionName, String memberName) {
    //make sure the command executor is a player
    if (!(sender instanceof Player)) {
        sender.sendMessage("Sorry, only players can execute this command");
        return;
    }
    if (Bukkit.getPlayer(memberName) == null) {
        //player isn't currently online with thtat name
        sender.sendMessage("This player is not currently online!");
        return;
    }
    //assuming if they have an account, they are a valid identity to add as a member
    if (!LandPurchasing.economy.hasAccount(Bukkit.getOfflinePlayer(memberName))) {
        sender.sendMessage(memberName + " is not an existing player");
        return;
    }
    //get the region manager for the homeworld
    RegionManager rm = LandPurchasing.wgplugin.getRegionManager(Bukkit.getWorld("HomeWorld"));
    if (rm == null) {
        sender.sendMessage("No region manager for the homeworld");
        return;
    }
    //get the region in question
    ProtectedRegion region = rm.getRegion(((Player) sender).getUniqueId().toString() + "__" + regionName);
    if (region == null) {
        sender.sendMessage("No such region was found.");
        return;
    }
    //make sure the command executor is an owner of the plot
    if (!region.isOwner(new BukkitPlayer(wgplugin, Bukkit.getPlayer(memberName)))) {
        sender.sendMessage("You are not the owner of the specified region");
        return;
    }
    //add the player
    DefaultDomain d = region.getMembers();
    d.addPlayer(Bukkit.getPlayer(memberName).getUniqueId());
    region.setMembers(d);
    sender.sendMessage(memberName + " is now a member of the plot " + regionName);
}

[Buggy Hunk]
if(!region.isOwner(new BukkitPlayer(wgplugin, Bukkit.getPlayer(memberName)))){

[Patch]
if(!region.isOwner(new BukkitPlayer(wgplugin, (Player) sender))){

[Demonstration 2]

[Buggy Method]
public Executor getExecutor(Executor executor) {
    return runnable -> {
        synchronized (lock) {
            Task task = new Task(runnable, executor);
            if (last != null) {
                last.next = task;
                last = task;
            } else {
                last = task;
                executor.execute(task);
            }
        }
    };
}

[Buggy Hunk]
public Executor getExecutor(Executor executor) {

[Patch]
Executor getExecutor(Executor executor) {

[Demonstration 3]

[Buggy Method]
public static Result service(String ownerName, String projectName, String service, boolean isAdvertise) throws IOException, UnsupportedOperationException, ServletException {
    if (!isSupportedService(service)) {
        return forbidden(String.format("Unsupported service: '%s'", service));
    }
    Project project = Project.findByOwnerAndProjectName(ownerName, projectName);
    if (project == null) {
        return notFound();
    }
    models.User user = UserApp.currentUser();
    if (!isAllowed(project, service)) {
        if (user.isAnonymous()) {
            return BasicAuthAction.unauthorized(response());
        } else {
            // If you want the Git client showing your custom message to
            // the user, the Content-Type should be exact "text/plain"
            // without any parameter. For more details, see the code at
            // https://github.com/git/git/commit/426e70d4a11ce3b4f70636d57c6a0ab16ae08a00#diff-eea0ad565ec5903a11b6023755d491cfR154
            response().setHeader("Content-Type", "text/plain");
            return forbidden(String.format("'%s' has no permission to '%s/%s'.", user.name, ownerName, projectName));
        }
    }
    if (isAdvertise) {
        return ok(RepositoryService.gitAdvertise(project, service, response()));
    } else {
        if (request().body().isMaxSizeExceeded()) {
            return status(REQUEST_ENTITY_TOO_LARGE);
        } else {
            user.visits(project);
            return ok(RepositoryService.gitRpc(project, service, request(), response()));
        }
    }
}

[Buggy Hunk]
user.name, ownerName, projectName));

[Patch]
user.loginId, ownerName, projectName));