Bulk operations (e.g. bulk watching issues) can cause a stack trace with ConcurrentModificationException

java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901)
at java.util.ArrayList$Itr.next(ArrayList.java:851)
at com.atlassian.jira.bc.issue.watcher.DefaultWatcherService.canWatchAll(DefaultWatcherService.java:211)
at com.atlassian.jira.bulkedit.operation.BulkWatchOperation.canPerform(BulkWatchOperation.java:30)
at com.atlassian.jira.web.action.issue.bulkedit.BulkChooseOperation.isCanPerform(BulkChooseOperation.java:102)
at com.atlassian.jira.web.action.issue.bulkedit.BulkChooseOperation.isCanPerform(BulkChooseOperation.java:98)
... 2 filtered
at java.lang.reflect.Method.invoke(Method.java:483)
at webwork.util.InjectionUtils$DefaultInjectionImpl.invoke(InjectionUtils.java:70)
at webwork.util.InjectionUtils.invoke(InjectionUtils.java:56)
at webwork.util.ValueStack.findValue(ValueStack.java:517)
at webwork.util.SimpleTest.test(SimpleTest.java:408)
at webwork.util.ValueStack.test(ValueStack.java:157)
at webwork.view.taglib.IfTag.doStartTag(IfTag.java:40)
at jsp.secure.views.bulkedit.bulkchooseoperation_jsp._jspx_meth_ww_005fif_005f1(bulkchooseoperation_jsp.java:1308)
at jsp.secure.views.bulkedit.bulkchooseoperation_jsp._jspx_meth_ww_005fiterator_005f0(bulkchooseoperation_jsp.java:1257)
at jsp.secure.views.bulkedit.bulkchooseoperation_jsp._jspService(bulkchooseoperation_jsp.java:218)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
... 22 filtered
at com.atlassian.servicedesk.internal.web.ExternalCustomerLockoutFilter.doFilter(ExternalCustomerLockoutFilter.java:56)
... 4 filtered
at com.atlassian.web.servlet.plugin.request.RedirectInterceptingFilter.doFilter(RedirectInterceptingFilter.java:21)
... 22 filtered
at com.atlassian.jira.plugins.rest.HOT25715FixServletFilter.doFilter(HOT25715FixServletFilter.java:46)
... 26 filtered
at com.atlassian.jira.security.JiraSecurityFilter.lambda$doFilter$0(JiraSecurityFilter.java:76)
at com.atlassian.jira.security.JiraSecurityFilter$$Lambda$2355/476696057.doFilter(Unknown Source)
... 1 filtered
at com.atlassian.jira.security.JiraSecurityFilter.doFilter(JiraSecurityFilter.java:74)
... 17 filtered
at com.atlassian.servicedesk.plugins.cm.internal.auth.filter.LocalServiceDeskUserAuthenticationFilter.doFilter(LocalServiceDeskUserAuthenticationFilter.java:99)
... 13 filtered
at com.atlassian.servicedesk.internal.web.CustomerContextSettingFilter.doFilter(CustomerContextSettingFilter.java:130)
... 23 filtered
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at com.atlassian.jira.servlet.WebExceptionCheckingServlet.delegate(WebExceptionCheckingServlet.java:86)
at com.atlassian.jira.servlet.WebExceptionCheckingServlet.service(WebExceptionCheckingServlet.java:32)
... 26 filtered
at com.atlassian.servicedesk.internal.web.ExternalCustomerLockoutFilter.doFilter(ExternalCustomerLockoutFilter.java:56)
... 4 filtered
at com.atlassian.greenhopper.jira.filters.ClassicBoardRouter.doFilter(ClassicBoardRouter.java:56)
... 13 filtered
at com.atlassian.web.servlet.plugin.request.RedirectInterceptingFilter.doFilter(RedirectInterceptingFilter.java:21)
... 20 filtered
at com.atlassian.jira.plugins.rest.HOT25715FixServletFilter.doFilter(HOT25715FixServletFilter.java:46)
... 30 filtered
at com.atlassian.plugin.connect.plugin.auth.scope.ApiScopingFilter.doFilter(ApiScopingFilter.java:81)
... 3 filtered
at com.atlassian.jira.plugins.hipchat.web.filter.TaskSchedulerFilter.doFilter(TaskSchedulerFilter.java:38)
... 14 filtered
at com.atlassian.jira.security.JiraSecurityFilter.lambda$doFilter$0(JiraSecurityFilter.java:76)
at com.atlassian.jira.security.JiraSecurityFilter$$Lambda$2355/476696057.doFilter(Unknown Source)
... 1 filtered
at com.atlassian.jira.security.JiraSecurityFilter.doFilter(JiraSecurityFilter.java:74)
... 20 filtered
at com.atlassian.servicedesk.plugins.cm.internal.auth.filter.LocalServiceDeskUserAuthenticationFilter.doFilter(LocalServiceDeskUserAuthenticationFilter.java:107)
... 8 filtered
at com.atlassian.studio.jira.homepage.CloudHomepageFilter$Action.lambda$nextInFilterChain$1(CloudHomepageFilter.java:115)
at com.atlassian.studio.jira.homepage.CloudHomepageFilter$Action$$Lambda$2347/1572948687.execute(Unknown Source)
at com.atlassian.studio.jira.homepage.CloudHomepageFilter.doFilter(CloudHomepageFilter.java:73)
at com.atlassian.studio.jira.homepage.CloudHomepageFilter$Provider.doFilter(CloudHomepageFilter.java:134)
... 18 filtered
at com.atlassian.plugin.connect.plugin.auth.oauth2.DefaultSalAuthenticationFilter.doFilter(DefaultSalAuthenticationFilter.java:76)
... 3 filtered
at com.atlassian.plugin.connect.plugin.auth.user.ThreeLeggedAuthFilter.doFilter(ThreeLeggedAuthFilter.java:111)
... 3 filtered
at com.atlassian.servicedesk.internal.web.CustomerContextSettingFilter.lambda$invokeFilterChain$0(CustomerContextSettingFilter.java:195)
at com.atlassian.servicedesk.internal.web.CustomerContextSettingFilter$$Lambda$2334/1727172903.call(Unknown Source)
at com.atlassian.servicedesk.internal.utils.context.ReentrantThreadLocalBasedCodeContext.rteInvoke(ReentrantThreadLocalBasedCodeContext.java:139)
at com.atlassian.servicedesk.internal.utils.context.ReentrantThreadLocalBasedCodeContext.runOutOfContext(ReentrantThreadLocalBasedCodeContext.java:92)
at com.atlassian.servicedesk.internal.utils.context.CustomerContextServiceImpl.runOutOfCustomerContext(CustomerContextServiceImpl.java:64)
at com.atlassian.servicedesk.internal.web.CustomerContextSettingFilter.outOfCustomerContext(CustomerContextSettingFilter.java:188)
at com.atlassian.servicedesk.internal.web.CustomerContextSettingFilter.doFilterImpl(CustomerContextSettingFilter.java:144)
at com.atlassian.servicedesk.internal.web.CustomerContextSettingFilter.doFilter(CustomerContextSettingFilter.java:135)
... 4 filtered
at com.atlassian.jwt.internal.servlet.JwtAuthFilter.doFilter(JwtAuthFilter.java:32)
... 8 filtered
at com.atlassian.web.servlet.plugin.request.RedirectInterceptingFilter.doFilter(RedirectInterceptingFilter.java:21)
... 4 filtered
at com.atlassian.web.servlet.plugin.LocationCleanerFilter.doFilter(LocationCleanerFilter.java:36)
... 40 filtered
at com.atlassian.jira.util.zipkin.ZipkinTracingFilter.lambda$doFilter$1(ZipkinTracingFilter.java:52)
at com.atlassian.jira.util.zipkin.ZipkinTracingFilter$$Lambda$2232/1110970069.doFilter(Unknown Source)
at com.github.kristofa.brave.servlet.BraveServletFilter.doFilter(BraveServletFilter.java:59)
at com.atlassian.jira.util.zipkin.ZipkinTracingFilter.doFilter(ZipkinTracingFilter.java:40)
... 21 filtered
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)