Task

public class CronServiceTask implements PluginJob {

    public static final String MAIL = "mail";
    private MultiQueueTaskManager taskManager;
    private SearchService searchService;
    SearchResults searchResults;
    
    
    public void execute(Map<String, Object> jobDataMap) {

        Email email = new Email("ardibest@gmail.com");
        email.setBody("Hello");
        email.setMimeType("text/plain");
        email.setSubject("Example Subject");
        SingleMailQueueItem item = new SingleMailQueueItem(email);
        final MailServiceImpl mailService = new MailServiceImpl(taskManager);
        mailService.sendEmail(item);
        final CronServiceImpl monitor = (CronServiceImpl) jobDataMap.get(CronServiceImpl.KEY);
        assert monitor != null;
        final List<Issue> issues = this.recieveIssues();
        monitor.setIssues(issues);
    }

    private List<Issue> recieveIssues() {

        ApplicationUser applicationUser = ComponentAccessor.getJiraAuthenticationContext().getUser();
        User user = ApplicationUsers.toDirectoryUser(applicationUser); // null pointer
        
        JqlClauseBuilder jqlClauseBuilder = JqlQueryBuilder.newClauseBuilder();
        Query query = jqlClauseBuilder.project("Project").buildQuery();
        PagerFilter pagerFilter = PagerFilter.getUnlimitedFilter();

        try {
            searchResults = searchService.search(user, query, pagerFilter);   // perform search results
        } catch (SearchException e) {
            e.printStackTrace();
        }
        return searchResults.getIssues();  // return the results
    }
}