Attempting to import issues from GitHub fails with an UnsupportedOperationException

Referer URL: http://54.94.26.141:8080/secure/admin/views/GithubSetupPage!default.jspa?externalSystem=com.atlassian.jira.plugins.jira-importers-github-plugin:githubImporterKey
java.lang.UnsupportedOperationException
java.lang.UnsupportedOperationException
	at com.google.gson.JsonElement.getAsString(JsonElement.java:188)
	at com.atlassian.jira.plugins.importer.github.fetch.auth.GithubAuthenticatorImpl.getTokenFromAuthorizations(GithubAuthenticatorImpl.java:188)
	at com.atlassian.jira.plugins.importer.github.fetch.auth.GithubAuthenticatorImpl.handleTokenAlreadyExists(GithubAuthenticatorImpl.java:170)
	at com.atlassian.jira.plugins.importer.github.fetch.auth.GithubAuthenticatorImpl.getAccessToken(GithubAuthenticatorImpl.java:129)
	at com.atlassian.jira.plugins.importer.github.fetch.auth.GithubAuthenticatorImpl.authenticateGithub(GithubAuthenticatorImpl.java:75)
	at com.atlassian.jira.plugins.importer.github.GithubImporterController.validateGithubEnterprise(GithubImporterController.java:82)
	at com.atlassian.jira.plugins.importer.github.GithubImporterController.createImportProcessBean(GithubImporterController.java:67)
	at com.atlassian.jira.plugins.importer.github.web.GithubSetupPage.doExecute(GithubSetupPage.java:105)
	at webwork.action.ActionSupport.execute(ActionSupport.java:165)
	at com.atlassian.jira.action.JiraActionSupport.execute(JiraActionSupport.java:87)
	at com.atlassian.jira.plugins.importer.web.ImporterProcessSupport.execute(ImporterProcessSupport.java:156)
	at webwork.interceptor.DefaultInterceptorChain.proceed(DefaultInterceptorChain.java:39)
	at webwork.interceptor.NestedInterceptorChain.proceed(NestedInterceptorChain.java:31)
	at webwork.interceptor.ChainedInterceptor.intercept(ChainedInterceptor.java:16)
	at webwork.interceptor.DefaultInterceptorChain.proceed(DefaultInterceptorChain.java:35)
	at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:225)
	at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:154)
	at com.atlassian.jira.web.dispatcher.JiraWebworkActionDispatcher.service(JiraWebworkActionDispatcher.java:152)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.web.filters.steps.ChainedFilterStepRunner.doFilter(ChainedFilterStepRunner.java:87)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.web.filters.XContentTypeOptionsNoSniffFilter.doFilter(XContentTypeOptionsNoSniffFilter.java:22)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.core.filters.HeaderSanitisingFilter.doFilter(HeaderSanitisingFilter.java:44)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.jira.tzdetect.IncludeResourcesFilter.doFilter(IncludeResourcesFilter.java:39)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.jira.baseurl.IncludeResourcesFilter.doFilter(IncludeResourcesFilter.java:38)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.applinks.core.rest.context.ContextFilter.doFilter(ContextFilter.java:25)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.mywork.client.filter.ServingRequestsFilter.doFilter(ServingRequestsFilter.java:37)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.prettyurls.filter.PrettyUrlsDispatcherFilter.doFilter(PrettyUrlsDispatcherFilter.java:60)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.prettyurls.filter.PrettyUrlsSiteMeshFilter.doFilter(PrettyUrlsSiteMeshFilter.java:92)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.prettyurls.filter.PrettyUrlsMatcherFilter.doFilter(PrettyUrlsMatcherFilter.java:56)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.labs.botkiller.BotKillerFilter.doFilter(BotKillerFilter.java:36)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.web.filters.accesslog.AccessLogFilter.executeRequest(AccessLogFilter.java:103)
	at com.atlassian.jira.web.filters.accesslog.AccessLogFilter.doFilter(AccessLogFilter.java:87)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.security.xsrf.XsrfTokenAdditionRequestFilter.doFilter(XsrfTokenAdditionRequestFilter.java:54)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:181)
	at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:85)
	at com.atlassian.jira.web.filters.SitemeshPageFilter.doFilter(SitemeshPageFilter.java:124)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.web.filters.steps.ChainedFilterStepRunner.doFilter(ChainedFilterStepRunner.java:87)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.prettyurls.filter.PrettyUrlsCombinedMatchDispatcherFilter.doFilter(PrettyUrlsCombinedMatchDispatcherFilter.java:61)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:234)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:100)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.seraph.filter.BaseLoginFilter.doFilter(BaseLoginFilter.java:169)
	at com.atlassian.jira.web.filters.JiraLoginFilter.doFilter(JiraLoginFilter.java:70)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.oauth.serviceprovider.internal.servlet.OAuthFilter.doFilter(OAuthFilter.java:61)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.prettyurls.filter.PrettyUrlsCombinedMatchDispatcherFilter.doFilter(PrettyUrlsCombinedMatchDispatcherFilter.java:61)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:99)
	at com.atlassian.jira.web.filters.JIRAProfilingFilter.doFilter(JIRAProfilingFilter.java:19)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.johnson.filters.AbstractJohnsonFilter.doFilter(AbstractJohnsonFilter.java:71)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176)
	at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)
	at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)
	at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:394)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.gzipfilter.GzipFilter.doFilterInternal(GzipFilter.java:74)
	at com.atlassian.gzipfilter.GzipFilter.doFilter(GzipFilter.java:51)
	at com.atlassian.jira.web.filters.gzip.JiraGzipFilter.doFilter(JiraGzipFilter.java:55)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.prettyurls.filter.PrettyUrlsCombinedMatchDispatcherFilter.doFilter(PrettyUrlsCombinedMatchDispatcherFilter.java:61)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.web.filters.steps.ChainedFilterStepRunner.doFilter(ChainedFilterStepRunner.java:87)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.core.filters.cache.AbstractCachingFilter.doFilter(AbstractCachingFilter.java:33)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.core.filters.encoding.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:41)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at com.atlassian.jira.web.filters.PathMatchingEncodingFilter.doFilter(PathMatchingEncodingFilter.java:49)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.startup.JiraStartupChecklistFilter.doFilter(JiraStartupChecklistFilter.java:78)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.web.filters.MultipartBoundaryCheckFilter.doFilter(MultipartBoundaryCheckFilter.java:41)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.atlassian.jira.web.filters.steps.ChainedFilterStepRunner.doFilter(ChainedFilterStepRunner.java:87)
	at com.atlassian.jira.web.filters.JiraFirstFilter.doFilter(JiraFirstFilter.java:57)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)