Error

VelocityViewServlet : Error processing a template for path '/WEB-INF/templates/detail/search_detail_idf_2_0.vm'

Invocation of method 'getListAPACitation' in class de.ingrid.portal.search.detail.idf.part.DetailPartPreparerIdfMetadata threw exception java.lang.NullPointerException: XPath expression-Argument darf nicht null sein at /WEB-INF/templates/detail/parts/metadata/settings/settings_bibliography.vm[line 11, column 37]
java.lang.NullPointerException: XPath expression-Argument darf nicht null sein
	at java.xml/com.sun.org.apache.xpath.internal.jaxp.XPathImplUtil.requireNonNull(Unknown Source)
	at java.xml/com.sun.org.apache.xpath.internal.jaxp.XPathImpl.evaluate(Unknown Source)
	at de.ingrid.utils.xpath.XPathUtils.getNode(XPathUtils.java:150)
	at de.ingrid.portal.search.detail.idf.part.DetailPartPreparerIdfMetadata.getAPACitationValueFromXpath(DetailPartPreparerIdfMetadata.java:802)
	at de.ingrid.portal.search.detail.idf.part.DetailPartPreparerIdfMetadata.getAPACitationElements(DetailPartPreparerIdfMetadata.java:758)
	at de.ingrid.portal.search.detail.idf.part.DetailPartPreparerIdfMetadata.getListAPACitation(DetailPartPreparerIdfMetadata.java:743)
	at jdk.internal.reflect.GeneratedMethodAccessor498.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:389)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:378)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:270)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:262)
	at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:507)
	at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:71)
	at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:142)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
	at org.apache.velocity.runtime.directive.Parse.render(Parse.java:263)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
	at org.apache.velocity.runtime.directive.Parse.render(Parse.java:263)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
	at org.apache.velocity.runtime.directive.Parse.render(Parse.java:263)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:366)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:212)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:247)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
	at org.apache.velocity.Template.merge(Template.java:328)
	at org.apache.velocity.Template.merge(Template.java:235)
	at org.apache.portals.bridges.velocity.BridgesVelocityViewServlet.mergeTemplate(BridgesVelocityViewServlet.java:119)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doRequest(VelocityViewServlet.java:551)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doGet(VelocityViewServlet.java:507)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:655)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:711)
	at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:578)
	at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:517)
	at org.apache.pluto.container.impl.PortletRequestDispatcherImpl.doDispatch(PortletRequestDispatcherImpl.java:174)
	at org.apache.pluto.container.impl.PortletRequestDispatcherImpl.include(PortletRequestDispatcherImpl.java:227)
	at org.apache.portals.bridges.common.GenericServletPortlet.doView(GenericServletPortlet.java:364)
	at org.apache.portals.bridges.velocity.GenericVelocityPortlet.doView(GenericVelocityPortlet.java:170)
	at de.ingrid.portal.portlets.SearchDetailPortlet.doView(SearchDetailPortlet.java:542)
	at javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:359)
	at javax.portlet.GenericPortlet.render(GenericPortlet.java:262)
	at org.apache.portals.bridges.velocity.GenericVelocityPortlet.render(GenericVelocityPortlet.java:176)
	at org.apache.jetspeed.portlet.PortletObjectProxy.proxyRender(PortletObjectProxy.java:279)
	at org.apache.jetspeed.portlet.PortletObjectProxy.invoke(PortletObjectProxy.java:171)
	at jdk.proxy6/jdk.proxy6.$Proxy287.render(Unknown Source)
	at org.apache.jetspeed.factory.JetspeedPortletInstance.render(JetspeedPortletInstance.java:117)
	at org.apache.jetspeed.container.services.JetspeedFilterChain.doFilter(JetspeedFilterChain.java:142)
	at org.apache.jetspeed.container.services.JetspeedFilterChain.processFilter(JetspeedFilterChain.java:92)
	at org.apache.jetspeed.container.services.JetspeedFilterManager.processFilter(JetspeedFilterManager.java:112)
	at org.apache.jetspeed.container.JetspeedContainerServlet.doGet(JetspeedContainerServlet.java:290)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:655)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:711)
	at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:578)
	at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:517)
	at org.apache.jetspeed.container.invoker.ServletPortletInvoker.invoke(ServletPortletInvoker.java:165)
	at org.apache.jetspeed.container.invoker.JetspeedPortletInvokerService.render(JetspeedPortletInvokerService.java:127)
	at org.apache.pluto.container.impl.PortletContainerImpl.doRender(PortletContainerImpl.java:157)
	at org.apache.jetspeed.container.JetspeedPortletContainerWrapper.doRender(JetspeedPortletContainerWrapper.java:69)
	at org.apache.jetspeed.aggregator.impl.RenderingJobImpl.executeInternal(RenderingJobImpl.java:245)
	at org.apache.jetspeed.aggregator.impl.RenderingJobImpl.execute(RenderingJobImpl.java:221)
	at org.apache.jetspeed.aggregator.impl.PortletRendererImpl.renderNow(PortletRendererImpl.java:178)
	at org.apache.jetspeed.aggregator.impl.PortletRendererImpl.renderNow(PortletRendererImpl.java:156)
	at org.apache.jetspeed.aggregator.impl.PageAggregatorImpl.aggregateAndRender(PageAggregatorImpl.java:108)
	at org.apache.jetspeed.aggregator.impl.PageAggregatorImpl.aggregateAndRender(PageAggregatorImpl.java:104)
	at org.apache.jetspeed.aggregator.impl.PageAggregatorImpl.build(PageAggregatorImpl.java:78)
	at org.apache.jetspeed.aggregator.AggregatorValve.invoke(AggregatorValve.java:46)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.aggregator.HeaderAggregatorValve.invoke(HeaderAggregatorValve.java:53)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.decoration.DecorationValve.invoke(DecorationValve.java:164)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.resource.ResourceValveImpl.invoke(ResourceValveImpl.java:84)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.pipeline.valve.impl.ActionValveImpl.invoke(ActionValveImpl.java:139)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.container.ContainerValve.invoke(ContainerValve.java:88)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.container.PageHistoryValve.invoke(PageHistoryValve.java:111)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.profiler.impl.RefreshUserHomepageValveImpl.invoke(RefreshUserHomepageValveImpl.java:114)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.pipeline.valve.impl.AbstractPageValveImpl.invoke(AbstractPageValveImpl.java:169)
	at org.apache.jetspeed.pipeline.valve.impl.PageProfilerValveImpl.invoke(PageProfilerValveImpl.java:57)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.security.impl.LoginValidationValveImpl.invoke(LoginValidationValveImpl.java:158)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.security.impl.PasswordCredentialValveImpl.invoke(PasswordCredentialValveImpl.java:174)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.localization.impl.LocalizationValveImpl.invoke(LocalizationValveImpl.java:171)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at de.ingrid.portal.jetspeed.localization.impl.IngridLocalizationValveImpl.invoke(IngridLocalizationValveImpl.java:122)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.security.impl.AbstractSecurityValve$1.run(AbstractSecurityValve.java:138)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at java.base/javax.security.auth.Subject.doAsPrivileged(Unknown Source)
	at org.apache.jetspeed.security.JSSubject.doAsPrivileged(JSSubject.java:187)
	at org.apache.jetspeed.security.impl.AbstractSecurityValve.invoke(AbstractSecurityValve.java:132)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.container.url.impl.PortalURLValveImpl.invoke(PortalURLValveImpl.java:88)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.capabilities.impl.CapabilityValveImpl.invoke(CapabilityValveImpl.java:127)
	at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:242)
	at org.apache.jetspeed.pipeline.JetspeedPipeline.invoke(JetspeedPipeline.java:163)
	at org.apache.jetspeed.engine.JetspeedEngine.service(JetspeedEngine.java:219)
	at org.apache.jetspeed.engine.JetspeedServlet.invoke(JetspeedServlet.java:301)
	at org.apache.jetspeed.engine.JetspeedServlet.service(JetspeedServlet.java:319)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:711)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:385)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:313)
	at org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:213)
	at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:171)
	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:381)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.jetspeed.container.session.PortalSessionValidationFilter.doFilter(PortalSessionValidationFilter.java:92)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at de.ingrid.portal.security.filter.XSSFilter.doFilter(XSSFilter.java:88)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.jetspeed.engine.servlet.XXSUrlAttackFilter.doFilter(XXSUrlAttackFilter.java:82)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.jetspeed.security.impl.shibboleth.ShibbolethPortalFilter.doFilter(ShibbolethPortalFilter.java:267)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.jetspeed.util.ServletRequestCleanupService.doFilter(ServletRequestCleanupService.java:146)
	at org.apache.jetspeed.util.ServletRequestCleanupFilter.doFilter(ServletRequestCleanupFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.authenticator.SingleSignOn.invoke(SingleSignOn.java:261)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
	at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:433)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1726)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.base/java.lang.Thread.run(Unknown Source)