[Demonstration 1]

[Buggy Method]
public boolean multiplicationNeeded(String checkFor) {
    String trimmedText = displayText.toString().replaceAll(" ", "");
    if (displayText.length() > 0) {
        String oneSpotBefore = trimmedText.charAt(trimmedText.length() - 1) + "";
        return oneSpotBefore.equals(checkFor);
    }
    return false;
}

[Buggy Hunk]
if (displayText.length() > 0){

[Patch]
if (displayText.length() > 0 && checkFor.equals("π")){

[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 boolean runCommandAndLogOutput(Configuration configuration, Logger log, File dir, String... commands) {
    File outputFile = new File(dir, "target/updatebot.log");
    File errorFile = new File(dir, "target/updatebot.err");
    try (FileDeleter ignored = new FileDeleter(outputFile, errorFile)) {
        outputFile.getParentFile().mkdirs();
        boolean answer = true;
        if (runCommand(dir, outputFile, errorFile, commands) != 0) {
            LOG.warn("Failed to run " + String.join(" ", commands));
            answer = false;
        }
        logOutput(configuration, log, outputFile, false);
        logOutput(configuration, log, errorFile, true);
        return answer;
    } catch (IOException e) {
        LOG.warn("Caught: " + e, e);
        return false;
    }
}

[Buggy Hunk]
LOG.warn("Failed to run " + String.join(" ", commands));

[Patch]
LOG.error("Failed to run " + String.join(" ", commands));