Apache Log4j Tag Library not working on tomcat 10.1.34

[pischky]

Description

I'm trying to port a project using JSP from Tomcat 9 to Tomcat 10.1.34 but "Apache Log4j Tag Library" ("log4j-taglib-2.24.3.jar")
is not working anymore.

Configuration

log4j-taglib-2.24.3.jar

Winows 7

Java 21.0.2 / Oracle

Logs

HTTP Status 500 – Internal Server Error

Type Exception Report

Message java.lang.NoClassDefFoundError: javax/servlet/jsp/tagext/BodyTagSupport

Beschreibung The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

jakarta.servlet.ServletException: java.lang.NoClassDefFoundError: javax/servlet/jsp/tagext/BodyTagSupport
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:70)

Root Cause

java.lang.NoClassDefFoundError: javax/servlet/jsp/tagext/BodyTagSupport
java.base/java.lang.ClassLoader.defineClass1(Native Method)
java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1027)
java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2350)
org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2219)
org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:813)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1335)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1183)
org.apache.jasper.compiler.Parser.parseCustomTag(Parser.java:1244)
org.apache.jasper.compiler.Parser.parseElements(Parser.java:1477)
org.apache.jasper.compiler.Parser.parse(Parser.java:138)
org.apache.jasper.compiler.ParserController.doParse(ParserController.java:264)
org.apache.jasper.compiler.ParserController.parse(ParserController.java:109)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:194)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:367)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:345)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:331)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:603)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:396)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:377)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:325)
jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:70)

Root Cause

java.lang.ClassNotFoundException: javax.servlet.jsp.tagext.BodyTagSupport
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1374)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1183)
java.base/java.lang.ClassLoader.defineClass1(Native Method)
java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1027)
java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2350)
org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2219)
org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:813)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1335)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1183)
org.apache.jasper.compiler.Parser.parseCustomTag(Parser.java:1244)
org.apache.jasper.compiler.Parser.parseElements(Parser.java:1477)
org.apache.jasper.compiler.Parser.parse(Parser.java:138)
org.apache.jasper.compiler.ParserController.doParse(ParserController.java:264)
org.apache.jasper.compiler.ParserController.parse(ParserController.java:109)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:194)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:367)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:345)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:331)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:603)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:396)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:377)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:325)
jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:70)

Hinweis Der komplette Stacktrace der Ursache ist in den Server logs zu finden

Reproduction

<%@ taglib prefix="log" uri="http://logging.apache.org/log4j/tld/log" %>
<log:setLogger logger="/index.jsp" />

[ppkarwasz]

I'm trying to port a project using JSP from Tomcat 9 to Tomcat 10.1.34 but "Apache Log4j Tag Library" ("log4j-taglib-2.24.3.jar")
is not working anymore.

The log4j-taglib artifact only supports JavaServer Pages 2.3 (part of Java EE 8) or earlier releases. As you are probably aware, Jakarta Server Pages 3.0 and later (part of Jakarta EE 9) uses a new jakarta.* namespace for classes, instead of the javax.* namespace, which is a breaking change. Currently we don't plan any version of log4j-taglib compatible with JSP 3.0 (see documentation) and the log4j-taglib artifact is scheduled for removal in Log4j Core 3.

Could you tell us more about your application? Are you still using log4j-taglib in production? There are multiple reasons for the deprecation:

• according to our download statistics, the log4j-taglib artifact is barely used.
• most of the tools we used to generate the artifact (e.g. taglib-maven-plugin) have gone EOL.
• since modern JSP pages are only used as HTML templates and don't contain Java code any more, we believe that the need for logging in a JSP page has disappeared.
• Apache Log4j has a lot of components and we don't have enough time to ensure that all the components are high quality. In particular log4j-taglib needs some love.

[pischky]

Thanks for the explanation. I will think about replacing log4j-taglib-2.24.3.jar in my project.