Error

VelocityViewServlet : Error processing the template

Invocation of method 'getSession' in  class org.apache.catalina.connector.RequestFacade threw exception java.lang.IllegalStateException: Cannot create a session after the response has been committed @ /WEB-INF/templates/template/header.vm[44,23]
org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getSession' in class org.apache.catalina.connector.RequestFacade threw exception java.lang.IllegalStateException: Cannot create a session after the response has been committed @ /WEB-INF/templates/template/header.vm[44,23] at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:286) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203) at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:419) at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:73) at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:125) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at org.apache.velocity.runtime.directive.Parse.render(Parse.java:224) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:170) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at org.apache.velocity.Template.merge(Template.java:254) at org.apache.velocity.tools.view.servlet.VelocityViewServlet.mergeTemplate(VelocityViewServlet.java:619) at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doRequest(VelocityViewServlet.java:434) at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doGet(VelocityViewServlet.java:392) at javax.servlet.http.HttpServlet.service(HttpServlet.java:621) at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 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 tenders.filter.IntecCsrfPreventionFilter.doFilter(IntecCsrfPreventionFilter.java:322) 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:219) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:492) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:165) at com.googlecode.psiprobe.Tomcat70AgentValve.invoke(Tomcat70AgentValve.java:38) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:452) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1195) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:654) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:319) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.IllegalStateException: Cannot create a session after the response has been committed at org.apache.catalina.connector.Request.doGetSession(Request.java:3177) at org.apache.catalina.connector.Request.getSession(Request.java:2499) at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:897) at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:909) at sun.reflect.GeneratedMethodAccessor190.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:245) ... 38 more