[Demonstration 1]

[Buggy Method]
private void requestProcess(RoutingContext context) {
    HttpServerRequest request = context.request();
    String eventParam = request.getParam("event");
    Event event = Event.getEventFromString(eventParam);
    JsonObject requestMessage = new JsonObject().put("from", this.getClass().getName()).put("date", LocalTime.now().toString());
    vertx.eventBus().send(event.name(), requestMessage, reply -> {
        if (reply.succeeded()) {
            if (logger.isDebugEnabled())
                logger.debug("Receive answer: " + reply.succeeded() + " body: " + reply.result().body());
            request.response().putHeader("content-type", "application/json; charset=utf-8").end(Json.encodePrettily(reply.result().body()));
        } else {
            if (logger.isDebugEnabled())
                logger.debug("error " + reply.cause());
        }
    });
}

[Buggy Hunk]
if(logger.isDebugEnabled()) logger.debug("error " + reply.cause());

[Patch]
if(logger.isDebugEnabled()) logger.error("error " + reply.cause());

[Demonstration 2]

[Buggy Method]
private static void tryDownload(String fileUrl, File file, String... customUrl) throws Exception {
    DLoader.debug("Attempting to download " + fileUrl);
    if (customUrl.length > 0 && !customUrl[0].isEmpty()) {
        openStream(customUrl[0] + fileUrl, (url, stream) -> pullFromStreamToFile(stream, url, file));
        return;
    }
    for (String url : REPOSITORIES) {
        final String actualUrl = url + fileUrl;
        DLoader.debug("URL is '" + actualUrl + "'");
        try {
            openStream(actualUrl, (fUrl, stream) -> pullFromStreamToFile(stream, fUrl, file));
            return;
        } catch (IOException e) {
            DLoader.log(Level.WARNING, "Failed to download from repo '" + url + "'");
        }
    }
    DLoader.log(Level.SEVERE, "Failed to download " + fileUrl);
}

[Buggy Hunk]
private static void tryDownload(String fileUrl, File file, String... customUrl) throws Exception {

[Patch]
private static void tryDownload(@NotNull String fileUrl, @NotNull File file, @NotNull String... customUrl) throws Exception {

[Demonstration 3]

[Buggy Method]
private void normalizesTo(String url, String result) {
    try {
        String normalized = new URILocator(url).getAddress();
        Assert.assertTrue("'" + url + "' normalized to '" + normalized + "'", normalized.equals(result));
    } catch (MalformedURLException e) {
        throw new OntopiaRuntimeException("ERROR: " + e);
    }
}

[Buggy Hunk]
Assert.assertTrue("'" + url + "' normalized to '" + normalized + "'",

[Patch]
assertTrue("'" + url + "' normalized to '" + normalized + "'",