output: #fixed code
                                protected static Set<String> getExpiredJobs(HelixDataAccessor dataAccessor,
        HelixPropertyStore propertyStore, WorkflowConfig workflowConfig,
        WorkflowContext workflowContext) {
      Set<String> expiredJobs = new HashSet<String>();
  
      if (workflowContext != null) {
        Map<String, TaskState> jobStates = workflowContext.getJobStates();
        for (String job : workflowConfig.getJobDag().getAllNodes()) {
          JobConfig jobConfig = TaskUtil.getJobConfig(dataAccessor, job);
          JobContext jobContext = TaskUtil.getJobContext(propertyStore, job);
          if (jobConfig == null) {
            LOG.error(String.format("Job %s exists in JobDAG but JobConfig is missing!", job));
            continue;
          }
          long expiry = jobConfig.getExpiry();
          if (expiry == workflowConfig.DEFAULT_EXPIRY || expiry < 0) {
            expiry = workflowConfig.getExpiry();
          }
          if (jobContext != null && jobStates.get(job) == TaskState.COMPLETED) {
            if (System.currentTimeMillis() >= jobContext.getFinishTime() + expiry) {
              expiredJobs.add(job);
            }
          }
        }
      }
      return expiredJobs;
    }
input: #vulnerable code 
                                protected static Set<String> getExpiredJobs(HelixDataAccessor dataAccessor,
        HelixPropertyStore propertyStore, WorkflowConfig workflowConfig,
        WorkflowContext workflowContext) {
      Set<String> expiredJobs = new HashSet<String>();
  
      if (workflowContext != null) {
        Map<String, TaskState> jobStates = workflowContext.getJobStates();
        for (String job : workflowConfig.getJobDag().getAllNodes()) {
          JobConfig jobConfig = TaskUtil.getJobConfig(dataAccessor, job);
          JobContext jobContext = TaskUtil.getJobContext(propertyStore, job);
          long expiry = jobConfig.getExpiry();
          if (expiry == workflowConfig.DEFAULT_EXPIRY || expiry < 0) {
            expiry = workflowConfig.getExpiry();
          }
          if (jobContext != null && jobStates.get(job) == TaskState.COMPLETED) {
            if (System.currentTimeMillis() >= jobContext.getFinishTime() + expiry) {
              expiredJobs.add(job);
            }
          }
        }
      }
      return expiredJobs;
    } 
                              #location 11 
                              #vulnerability type NULL_DEREFERENCE