Expression head is undefined on line 18, column 3 in news_content.html. The problematic instruction: ---------- ==> ${head} [on line 18, column 1 in news_content.html] ---------- Java backtrace for programmers: ---------- freemarker.core.InvalidReferenceException: Expression head is undefined on line 18, column 3 in news_content.html. at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:124) at freemarker.core.Expression.getStringValue(Expression.java:118) at freemarker.core.Expression.getStringValue(Expression.java:93) at freemarker.core.DollarVariable.accept(DollarVariable.java:76) at freemarker.core.Environment.visit(Environment.java:210) at freemarker.core.MixedContent.accept(MixedContent.java:92) at freemarker.core.Environment.visit(Environment.java:210) at freemarker.core.Environment.process(Environment.java:190) at freemarker.template.Template.process(Template.java:237) at com.pansoft.coal.erp.zmyq.gpw.mgr.StaticPagesMgr.processTemplate(StaticPagesMgr.java:324) at com.pansoft.coal.erp.zmyq.gpw.mgr.StaticPagesMgr.articleStatic(StaticPagesMgr.java:1102) at com.pansoft.coal.erp.zmyq.gpw.mgr.StaticPagesMgr.articleStatic(StaticPagesMgr.java:1307) at com.pansoft.coal.erp.zmyq.gpw.mgr.StaticPagesMgr$$FastClassByCGLIB$$ca12942d.invoke() at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149) at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:618) at com.pansoft.coal.erp.zmyq.gpw.mgr.StaticPagesMgr$$EnhancerByCGLIB$$17d39afc.articleStatic() at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.pansoft.coal.erp.util.Reflection.invokeMethod(Reflection.java:371) at com.pansoft.coal.erp.common.impl.InvokeObjectImpl.InvokeMethod(InvokeObjectImpl.java:397) at com.pansoft.coal.erp.common.impl.InvokeObjectImpl.Invoke(InvokeObjectImpl.java:328) at com.pansoft.coal.erp.workFlow.engine.FlowRunAction.RunAction(FlowRunAction.java:38) at com.pansoft.coal.erp.workFlow.engine.FlowAssist.createNextNodesInst(FlowAssist.java:621) at com.pansoft.coal.erp.workFlow.engine.FlowAssist.moveForward(FlowAssist.java:86) at com.pansoft.coal.erp.workFlow.engine.FlowDriver.driveOneNode(FlowDriver.java:74) at com.pansoft.coal.erp.workFlow.engine.FlowDriver.driveOneNode(FlowDriver.java:48) at com.pansoft.coal.erp.workFlow.engine.FlowDriver.sREngine(FlowDriver.java:36) at com.pansoft.coal.erp.workFlow.engine.FlowEngine.submitTask(FlowEngine.java:1290) at com.pansoft.coal.erp.workFlow.engine.FlowEngine._submitTask_new(FlowEngine.java:1394) at com.pansoft.coal.erp.workFlow.engine.FlowEngine.submitTask_new(FlowEngine.java:1327) at com.pansoft.coal.erp.workFlow.engine.FlowEngine.submitTask_new(FlowEngine.java:1309) at com.pansoft.coal.erp.workFlow.engine.FlowEngine$$FastClassByCGLIB$$bb525d9b.invoke() at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149) at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:689) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:622) at com.pansoft.coal.erp.workFlow.engine.FlowEngine$$EnhancerByCGLIB$$96315636.submitTask_new() at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.pansoft.coal.erp.util.Reflection.invokeMethod(Reflection.java:371) at com.pansoft.coal.erp.common.impl.InvokeObjectImpl.InvokeMethod(InvokeObjectImpl.java:397) at com.pansoft.coal.erp.common.impl.InvokeObjectImpl.Invoke(InvokeObjectImpl.java:328) at com.pansoft.coal.erp.common.impl.InvokeObjectImpl.Invoke(InvokeObjectImpl.java:312) at com.pansoft.coal.erp.common.impl.InvokeObjectImpl.InvokeMethod(InvokeObjectImpl.java:233) at com.pansoft.coal.erp.common.impl.InvokeObjectImpl.InvokeMethod(InvokeObjectImpl.java:72) at com.pansoft.coal.ws.impl.InvokeMethodServiceImpl.Invoke(InvokeMethodServiceImpl.java:25) at sun.reflect.GeneratedMethodAccessor92.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.cxf.service.invoker.AbstractInvoker.performInvocation(AbstractInvoker.java:173) at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:89) at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:165) at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:92) at org.apache.cxf.interceptor.ServiceInvokerInterceptor$1.run(ServiceInvokerInterceptor.java:58) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask.run(FutureTask.java:262) at org.apache.cxf.workqueue.SynchronousExecutor.execute(SynchronousExecutor.java:37) at org.apache.cxf.interceptor.ServiceInvokerInterceptor.handleMessage(ServiceInvokerInterceptor.java:106) at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:263) at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121) at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:207) at org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:209) at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:152) at org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:114) at org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:185) at org.apache.cxf.transport.servlet.AbstractHTTPServlet.doPost(AbstractHTTPServlet.java:108) at javax.servlet.http.HttpServlet.service(HttpServlet.java:650) at org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:164) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) 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:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745)