[Demonstration 1]

[Buggy Method]
private String replaceStatement(SQL sql, Map<String, Object> parameters) {
    String sqlContent = null;
    if (sql != null) {
        sqlContent = sql.getValue();
        if (StringUtils.isNotEmpty(sqlContent)) {
            try {
                // 执行子句构建 子句格式为{statement}
                List<Choose> chooseList = sql.getChooseList();
                if (chooseList != null && parameters != null) {
                    for (Choose choose : chooseList) {
                        String condition = choose.getWhen();
                        if (parameters.containsKey(condition)) {
                            String statement = choose.getStatement();
                            // 如果不存在statement参数，则使用when参数代替
                            if (StringUtils.isNotEmpty(statement)) {
                                statement = condition;
                            }
                            statement = "{" + statement + "}";
                            if (StringUtils.contains(sqlContent, statement)) {
                                sqlContent = sqlContent.replace(statement, choose.getValue());
                            } else {
                                sqlContent = sqlContent + " " + choose.getValue();
                            }
                        }
                    }
                }
                //清理没有被替换的子句
                //子句替换模式
                String regexs = "[{](\\w*)[}]";
                Pattern regex = Pattern.compile(regexs);
                Matcher regexMatcher = regex.matcher(sqlContent);
                while (regexMatcher.find()) {
                    sqlContent = sqlContent.replace(regexMatcher.group(0), "");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    return sqlContent;
}

[Buggy Hunk]
if (StringUtils.isNotEmpty(statement)) {

[Patch]
if (StringUtils.isEmpty(statement)) {

[Demonstration 2]

[Buggy Method]
public void setParameters(Expression[] parameters) {
    this.parameters = Arrays.copyOfRange(parameters, 0, parameters.length);
}

[Buggy Hunk]
this.parameters = Arrays.copyOfRange(parameters, 0, parameters.length);

[Patch]
this.parameters = parameters;

[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));