The following has evaluated to null or missing:
==> documents[0].getFieldValue  [in template "WEB-INF/free_marker/articledetail.ftl" at line 1, column 6]

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Tip: It's the step after the last dot that caused this error, not those before it.
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Tip: If the failing expression is known to be legally refer to something that's null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
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FTL stack trace ("~" means nesting-related):
	- Failed at: #if documents[0].getFieldValue("publi...  [in template "WEB-INF/free_marker/articledetail.ftl" at line 1, column 1]
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Java stack trace (for programmers):
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freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...]
	at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:116)
	at freemarker.core.UnexpectedTypeException.newDesciptionBuilder(UnexpectedTypeException.java:60)
	at freemarker.core.UnexpectedTypeException.<init>(UnexpectedTypeException.java:40)
	at freemarker.core.NonMethodException.<init>(NonMethodException.java:46)
	at freemarker.core.MethodCall._eval(MethodCall.java:84)
	at freemarker.core.Expression.eval(Expression.java:78)
	at freemarker.core.Expression.evalAndCoerceToString(Expression.java:82)
	at freemarker.core.BuiltInForString._eval(BuiltInForString.java:26)
	at freemarker.core.Expression.eval(Expression.java:78)
	at freemarker.core.EvalUtil.compare(EvalUtil.java:110)
	at freemarker.core.ComparisonExpression.evalToBoolean(ComparisonExpression.java:64)
	at freemarker.core.AndExpression.evalToBoolean(AndExpression.java:32)
	at freemarker.core.IfBlock.accept(IfBlock.java:46)
	at freemarker.core.Environment.visit(Environment.java:312)
	at freemarker.core.Environment.process(Environment.java:290)
	at freemarker.template.Template.process(Template.java:312)
	at org.apache.struts2.views.freemarker.FreemarkerResult.doExecute(FreemarkerResult.java:202)
	at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:373)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:277)
	at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263)
	at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:133)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:142)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:166)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:190)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:485)
	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
	at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:190)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)