JSF EL Expression paring Error

[Prakash .R]

Hi, im recently upgraded wildfly to 26.1.3 from 14 and our application is developed on JSF 1.2. Im facing an issue in one of the jsf page where we are using el expression to evaluate Boolean expression eg ${app.flag!='N'}. please find the below stacktrace. could any help to resolve this.

java.lang.NumberFormatException: For input string: "N" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.lang.Long.parseLong(Long.java:589) at java.lang.Long.valueOf(Long.java:803) at com.sun.el.lang.ELSupport.coerceToNumber(ELSupport.java:276) at com.sun.el.lang.ELSupport.coerceToNumber(ELSupport.java:258) at com.sun.el.lang.ELSupport.equals(ELSupport.java:126) at com.sun.el.parser.AstNotEqual.getValue(AstNotEqual.java:36) at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:183) at com.sun.facelets.el.TagValueExpression.getValue(TagValueExpression.java:71) at javax.faces.component.UIOutput.getValue(UIOutput.java:184) at com.bally.acsc.custom.components.html.ACSCCustomOutputText.encodeEnd(ACSCCustomOutputText.java:61) at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:242) at com.sun.faces.renderkit.html_basic.GroupRenderer.encodeChildren(GroupRenderer.java:106) at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:837) at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:234) at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:178) at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:126) at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:837) at org.ajax4jsf.renderkit.RendererBase.renderChild(RendererBase.java:277) at org.ajax4jsf.renderkit.RendererBase.renderChildren(RendererBase.java:258) at org.richfaces.renderkit.html.PanelRenderer.doEncodeChildren(PanelRenderer.java:220) at org.richfaces.renderkit.html.PanelRenderer.doEncodeChildren(PanelRenderer.java:215) at org.ajax4jsf.renderkit.RendererBase.encodeChildren(RendererBase.java:120) at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:837) at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:234) at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:178) at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:126) at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:837) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:936) at javax.faces.render.Renderer.encodeChildren(Renderer.java:148) at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:837) at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:234) at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:239) at com.sun.faces.renderkit.html_basic.GroupRenderer.encodeChildren(GroupRenderer.java:106) at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:837) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:936) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:942) at com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:594) at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100) at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176) at org.openfaces.ajax.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:64) at org.openfaces.ajax.AjaxViewHandler.renderView(AjaxViewHandler.java:413) at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:109) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100) at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:266) at com.bally.acsc.system.CustomFacesServlet.service(CustomFacesServlet.java:70) at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74) at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129) at org.openfaces.util.ResourceFilter.doFilter(ResourceFilter.java:99) at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:301) at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178) at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290) at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:368) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:495) at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) at com.bally.acsc.login.ACSCAuthenticationFilter.doFilter(ACSCAuthenticationFilter.java:326) at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84) at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68) at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) at org.wildfly.elytron.web.undertow.server.ElytronRunAsHandler.lambda$handleRequest$1(ElytronRunAsHandler.java:68) at org.wildfly.security.auth.server.FlexibleIdentityAssociation.runAsFunctionEx(FlexibleIdentityAssociation.java:103) at org.wildfly.security.auth.server.Scoped.runAsFunctionEx(Scoped.java:161) at org.wildfly.security.auth.server.Scoped.runAs(Scoped.java:73) at org.wildfly.elytron.web.undertow.server.ElytronRunAsHandler.handleRequest(ElytronRunAsHandler.java:67) at io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68) at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:117) at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) at org.wildfly.elytron.web.undertow.server.servlet.CleanUpHandler.handleRequest(CleanUpHandler.java:38) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at org.wildfly.extension.undertow.deployment.GlobalRequestControllerHandler.handleRequest(GlobalRequestControllerHandler.java:68) at io.undertow.servlet.handlers.SendErrorPageHandler.handleRequest(SendErrorPageHandler.java:52) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:275) at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:79) at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:134) at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:131) at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48) at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1544) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1544) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1544) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1544) at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:255) at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:79) at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:100) at io.undertow.server.Connectors.executeRootHandler(Connectors.java:387) at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:852) at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1990) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377) at org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282) at java.lang.Thread.run(Thread.java:748)  

[Paul Ferraro]

According to the EL specification, 'N' is not a valid boolean literal.

https://github.com/jakartaee/expression-language/blob/4.0.0/spec/src/main/asciidoc/ELSpec.adoc#13-literals