#vulnerable code 
                                public void check(GitlabMergeRequest gitlabMergeRequest) {
        if (_iid == null) {
            _iid = gitlabMergeRequest.getIid();
        }

        if (_targetBranch == null) {
            _targetBranch = gitlabMergeRequest.getTargetBranch();
        }

        if (_sourceBranch == null) {
            _sourceBranch = gitlabMergeRequest.getSourceBranch();
        }

        if (_sourceProject == null) {
            try {
                GitlabAPI api = _builder.getGitlab().get();
                _sourceProject = getSourceProject(gitlabMergeRequest, api);
            } catch (IOException e) {
                _logger.log(Level.SEVERE, "Failed to get source project for Merge request " + gitlabMergeRequest.getId() + " :\n" + e.getMessage());
                return;
            }
        }
        
        try {
            GitlabAPI api = _builder.getGitlab().get();
            GitlabNote lastJenkinsNote = getJenkinsNote(gitlabMergeRequest, api);
            GitlabCommit latestCommit = getLatestCommit(gitlabMergeRequest, api);

            if (lastJenkinsNote == null) {
                _shouldRun = true;
            } else {
                _shouldRun = latestCommitIsNotReached(latestCommit);
            }
            if (_shouldRun) {
            	_mergeRequestStatus.setLatestCommitOfMergeRequest(_id.toString(), latestCommit.getId());
            }
        } catch (IOException e) {
            _logger.log(Level.SEVERE, "Failed to fetch commits for Merge Request " + gitlabMergeRequest.getId());
        }

        if (_shouldRun) {
            build();
        }
    } 
                            #location 35 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public void check(GitlabMergeRequest gitlabMergeRequest) {

        if (_mergeRequestStatus == null) {
            _mergeRequestStatus = new GitlabMergeRequestStatus();
        }

        if (_iid == null) {
            _iid = gitlabMergeRequest.getIid();
        }

        if (_targetBranch == null) {
            _targetBranch = gitlabMergeRequest.getTargetBranch();
        }

        if (_sourceBranch == null) {
            _sourceBranch = gitlabMergeRequest.getSourceBranch();
        }

        if (_sourceProject == null) {
            try {
                GitlabAPI api = _builder.getGitlab().get();
                _sourceProject = getSourceProject(gitlabMergeRequest, api);
            } catch (IOException e) {
                _logger.log(Level.SEVERE, "Failed to get source project for Merge request " + gitlabMergeRequest.getId() + " :\n" + e.getMessage());
                return;
            }
        }
        
        try {
            GitlabAPI api = _builder.getGitlab().get();
            GitlabNote lastJenkinsNote = getJenkinsNote(gitlabMergeRequest, api);
            GitlabCommit latestCommit = getLatestCommit(gitlabMergeRequest, api);

            if (lastJenkinsNote == null) {
                _shouldRun = true;
            } else if (latestCommit == null) {
                _logger.log(Level.SEVERE, "Failed to determine the lastest commit for merge request {" + gitlabMergeRequest.getId() + "}. This might be caused by a stalled MR in gitlab.");
                return;
            } else {
                _shouldRun = latestCommitIsNotReached(latestCommit);
            }
            if (_shouldRun) {
            	_mergeRequestStatus.setLatestCommitOfMergeRequest(_id.toString(), latestCommit.getId());
            }
        } catch (IOException e) {
            _logger.log(Level.SEVERE, "Failed to fetch commits for Merge Request " + gitlabMergeRequest.getId());
        }

        if (_shouldRun) {
            build();
        }
    }