Hi, If you create a JSP and paste the following expression Tomcat fails executing it. Test ${not(true)} if you put a space between the "not" and "(" it works: Test ${not (true)} This worked in Tomcat 6.0.16 but not in Tomcat 6.0.18. This the exception that you get when it fails. Stacktrace: at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.ClassCastException: java.lang.NullPointerException cannot be cast to javax.el.ELException at org.apache.el.lang.ExpressionBuilder.prepare(ExpressionBuilder.java:135) at org.apache.el.lang.ExpressionBuilder.build(ExpressionBuilder.java:147) at org.apache.el.lang.ExpressionBuilder.createValueExpression(ExpressionBuilder.java:190) at org.apache.el.ExpressionFactoryImpl.createValueExpression(ExpressionFactoryImpl.java:68) at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:924) at org.apache.jsp.index_jsp._jspService(index_jsp.java:54) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374) ... 15 more Cheers Juan
*** This bug has been marked as a duplicate of bug 45511 ***