VelocityView : Error processing a template for path '/article.html'

org.apache.velocity.exception.VelocityException: Error invoking method 'get(java.lang.Integer)' in java.util.ArrayList at /article.html[line 36, column 42]
	at org.apache.velocity.runtime.parser.node.ASTIndex.execute(ASTIndex.java:218)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:369)
	at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:701)
	at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:72)
	at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:240)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:423)
	at org.apache.velocity.Template.merge(Template.java:358)
	at org.apache.velocity.Template.merge(Template.java:262)
	at org.apache.velocity.tools.view.VelocityView.performMerge(VelocityView.java:850)
	at org.apache.velocity.tools.view.VelocityView.merge(VelocityView.java:810)
	at org.apache.velocity.tools.view.VelocityViewServlet.mergeTemplate(VelocityViewServlet.java:366)
	at org.apache.velocity.tools.view.VelocityViewServlet.doRequest(VelocityViewServlet.java:239)
	at org.apache.velocity.tools.view.VelocityViewServlet.doGet(VelocityViewServlet.java:193)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at com.zwl.http.EncodingFilter.doFilter(EncodingFilter.java)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:475)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:341)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:495)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:767)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1354)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.GeneratedMethodAccessor54.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:565)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:548)
	at org.apache.velocity.runtime.parser.node.ASTIndex.execute(ASTIndex.java:192)
	... 38 more
Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
	at java.util.ArrayList.rangeCheck(ArrayList.java:653)
	at java.util.ArrayList.get(ArrayList.java:429)
	... 44 more