Expected collection or sequence. book.chapters evaluated instead to freemarker.template.SimpleHash on line 27, column 56 in book/view.ftl. The problematic instruction: ---------- ==> list book.chapters as x [on line 27, column 49 in book/view.ftl] ---------- Java backtrace for programmers: ---------- freemarker.template.TemplateException: Expected collection or sequence. book.chapters evaluated instead to freemarker.template.SimpleHash on line 27, column 56 in book/view.ftl. at freemarker.core.TemplateObject.invalidTypeException(TemplateObject.java:135) at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:190) at freemarker.core.Environment.visit(Environment.java:416) at freemarker.core.IteratorBlock.accept(IteratorBlock.java:102) at freemarker.core.Environment.visit(Environment.java:209) at freemarker.core.MixedContent.accept(MixedContent.java:92) at freemarker.core.Environment.visit(Environment.java:209) at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:79) at freemarker.core.Environment.visit(Environment.java:209) at freemarker.core.MixedContent.accept(MixedContent.java:92) at freemarker.core.Environment.visit(Environment.java:209) at freemarker.core.Environment.process(Environment.java:189) at freemarker.template.Template.process(Template.java:237) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.processTemplate(FreeMarkerView.java:366) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.doRender(FreeMarkerView.java:283) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.renderMergedTemplateModel(FreeMarkerView.java:233) at org.springframework.web.servlet.view.AbstractTemplateView.renderMergedOutputModel(AbstractTemplateView.java:167) at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250) at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1047) at org.codehaus.groovy.grails.web.servlet.GrailsDispatcherServlet.doDispatch(GrailsDispatcherServlet.java:329) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549) at javax.servlet.http.HttpServlet.service(HttpServlet.java:690) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:70) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:70) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:70) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:654) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:445) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:379) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:292) at org.codehaus.groovy.grails.web.util.WebUtils.forwardRequestForUrlMappingInfo(WebUtils.java:298) at org.codehaus.groovy.grails.web.util.WebUtils.forwardRequestForUrlMappingInfo(WebUtils.java:264) at org.codehaus.groovy.grails.web.util.WebUtils.forwardRequestForUrlMappingInfo(WebUtils.java:255) at org.codehaus.groovy.grails.web.mapping.filter.UrlMappingsFilter.doFilterInternal(UrlMappingsFilter.java:183) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.codehaus.groovy.grails.web.servlet.mvc.GrailsWebRequestFilter.doFilterInternal(GrailsWebRequestFilter.java:69) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.codehaus.groovy.grails.web.filters.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:69) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:654) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:445) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:379) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:292) at javax.servlet.RequestDispatcher$forward.call(Unknown Source) at util.RoleFilter.doFilter(RoleFilter.groovy:101) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:662)