[Demonstration 1]

[Buggy Method]
private void setProperty(PrefixExpression assignment, String section) {
    String key = section;
    if (assignment.operator.text.equals("_")) {
        if (StringUtils.isNullOrBlank(section)) {
            throw new IllegalStateException("Trying to set a non-section value using the \"_\" property.");
        }
        key = section.substring(0, section.length() - 1);
    } else {
        key = section + assignment.operator.text;
    }
    String value = assignment.right.as(ValueExpression.class).value;
    //unescape things
    value = StringUtils.trim(value);
    value = value.replaceAll("(?<!\\\\)\\\\\n", "\n");
    value = value.replaceAll("\\\\(.)", "$1");
    if (assignment.operator.type == ConfigTokenizer.ConfigTokenType.APPEND_PROPERTY) {
        if (Config.hasProperty(key)) {
            value = Config.get(key).asString() + "," + value;
        }
    }
    propertySetter.setProperty(key, value, resourceName);
}

[Buggy Hunk]
propertySetter.setProperty(key, value, resourceName);

[Patch]
Config.getInstance().setterFunction.setProperty(key, value, resourceName);

[Demonstration 2]

[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));

[Demonstration 3]

[Buggy Method]
public static String musicNotesToSearchString(String notes) {
    notes = notes.toLowerCase().replaceAll("\\s*[\\(\\[\"][^\\)]*[\\)\\]\"]\\s*", "");
    notes = notes.replaceAll("[^a-g]", "");
    String latestLetter = "";
    String[] letterArray = notes.split("");
    String result = "";
    for (String letter : letterArray) {
        if (!letter.equals(latestLetter)) {
            result += letter;
            latestLetter = letter;
        }
    }
    return result;
}

[Buggy Hunk]
notes = notes.toLowerCase().replaceAll("\\s*[\\(\\[\"][^\\)]*[\\)\\]\"]\\s*", "");

[Patch]
notes = notes.toLowerCase().replaceAll("\\s*[\\[\"][^\\)]*[\\]\"]\\s*", "");