Java method "com.bupticet.cms.web.action.ContentAction.getCategories()" threw an exception when invoked on com.bupticet.cms.web.action.ContentAction object "com.bupticet.cms.web.action.ContentAction@3f635064"; see cause exception in the Java stack trace.

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FTL stack trace ("~" means nesting-related):
	- Failed at: #assign categories = action.getCatego...  [in template "WEB-INF/config/site_templates/school_2/category_temp/default/left_nav.ftl" at line 1, column 58]
	- Reached through: #include "left_nav.ftl"  [in template "WEB-INF/config/site_templates/school_2/category_temp/default/catetory.ftl" at line 13, column 9]
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Java stack trace (for programmers):
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freemarker.core._TemplateModelException: [... Exception message was already printed; see it above ...]
	at freemarker.ext.beans._MethodUtil.newInvocationTemplateModelException(_MethodUtil.java:311)
	at freemarker.ext.beans._MethodUtil.newInvocationTemplateModelException(_MethodUtil.java:275)
	at freemarker.ext.beans.SimpleMethodModel.exec(SimpleMethodModel.java:80)
	at freemarker.core.MethodCall._eval(MethodCall.java:62)
	at freemarker.core.Expression.eval(Expression.java:78)
	at freemarker.core.Assignment.accept(Assignment.java:70)
	at freemarker.core.Environment.visit(Environment.java:312)
	at freemarker.core.MixedContent.accept(MixedContent.java:62)
	at freemarker.core.Environment.visit(Environment.java:312)
	at freemarker.core.EscapeBlock.accept(EscapeBlock.java:48)
	at freemarker.core.Environment.visit(Environment.java:312)
	at freemarker.core.Environment.include(Environment.java:2074)
	at freemarker.core.Include.accept(Include.java:165)
	at freemarker.core.Environment.visit(Environment.java:312)
	at freemarker.core.MixedContent.accept(MixedContent.java:62)
	at freemarker.core.Environment.visitByHiddingParent(Environment.java:333)
	at freemarker.core.IfBlock.accept(IfBlock.java:48)
	at freemarker.core.Environment.visit(Environment.java:312)
	at freemarker.core.MixedContent.accept(MixedContent.java:62)
	at freemarker.core.Environment.visit(Environment.java:312)
	at freemarker.core.EscapeBlock.accept(EscapeBlock.java:48)
	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:223)
	at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:191)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:372)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:276)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245)
	at com.filter.XssJsoupInterceptor.intercept(XssJsoupInterceptor.java:27)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245)
	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:245)
	at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:575)
	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:153)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
	at com.bupticet.ilab.filter.IlabFilter.doFilterInternal(IlabFilter.java:107)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at com.bupticet.filter.SetClientInfoFilter.doFilterInternal(SetClientInfoFilter.java:60)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:153)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	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:381)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at com.bupticet.clickstream.filter.VisitRecordFilter.doFilterInternal(VisitRecordFilter.java:126)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:153)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at com.bupticet.filter.ForceNoCacheFilter.doFilterInternal(ForceNoCacheFilter.java:98)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:153)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:140)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:153)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at com.bupticet.filter.LoginModuleFilter.doFilterInternal(LoginModuleFilter.java:104)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:153)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
	at com.bupticet.educonfig.filter.TermConfigFilter.doFilterInternal(TermConfigFilter.java:30)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at com.bupticet.filter.WrapperFilter.doFilter(WrapperFilter.java:153)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at com.bupticet.file.filter.FileLoadFilter.doFilter(FileLoadFilter.java:42)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:179)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:154)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:481)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:670)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:390)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:928)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1786)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	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:63)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -1
	at java.lang.String.substring(String.java:1967)
	at com.bupticet.cms.web.action.ContentAction.getCategories(ContentAction.java:684)
	at sun.reflect.GeneratedMethodAccessor914.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at freemarker.ext.beans.BeansWrapper.invokeMethod(BeansWrapper.java:1458)
	at freemarker.ext.beans.SimpleMethodModel.exec(SimpleMethodModel.java:71)
	... 107 more