"The absolute uri: http://java.sun.com/jstl/core cannot be resolved"

Question

I have been scouring the web to find the exact reason/fix for my situation. I have visited these other links on this site:

How to install JSTL? The absolute uri: http://java.sun.com/jstl/core cannot be resolved

https://stackoverflow.com/tags/jstl/info

JSTL 1.2 The absolute uri: http://java.sun.com/jsp/jstl/core cannot be resolved

And have still come up with the same error when I attempt to build the war file for my site. Earlier it was working on Tomcat 8.5.35. I had updated it to Tomcat 9.0.37 and it all went down the drain. I have updated the Build paths, the environment variables. I have made sure that all other files such as my library and framework files are also updated. I have made sure the build.properties file has the correct tomcat version. In the WEB-INF/web.xml file I have updated the servlet to 4.0 as Tomcat 9 supports. I have added jstl1.2.jar in WEB-INF/lib folder with the other jars my site needs.

Exception:

 [jasper] Jul 20, 2020 3:11:08 PM org.apache.jasper.servlet.TldScanner scanJars
   [jasper] INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
   [jasper] Jul 20, 2020 3:11:10 PM org.apache.jasper.JspC execute
   [jasper] SEVERE: Compilation error
   [jasper] java.util.concurrent.ExecutionException: org.apache.jasper.JasperException: The absolute uri: [http://java.sun.com/jsp/jstl/core] cannot be resolved in either web.xml or the jar files deployed with this application
   [jasper]     at java.util.concurrent.FutureTask.report(FutureTask.java:122)
   [jasper]     at java.util.concurrent.FutureTask.get(FutureTask.java:192)
   [jasper]     at org.apache.jasper.JspC.execute(JspC.java:1529)
   [jasper]     at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
   [jasper]     at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
   [jasper]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   [jasper]     at java.lang.reflect.Method.invoke(Method.java:498)
   [jasper]     at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:99)
   [jasper]     at org.apache.tools.ant.Task.perform(Task.java:350)
   [jasper]     at org.apache.tools.ant.Target.execute(Target.java:449)
   [jasper]     at org.apache.tools.ant.Target.performTasks(Target.java:470)
   [jasper]     at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1391)
   [jasper]     at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
   [jasper]     at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
   [jasper]     at org.eclipse.ant.internal.launching.remote.EclipseDefaultExecutor.executeTargets(EclipseDefaultExecutor.java:36)
   [jasper]     at org.apache.tools.ant.Project.executeTargets(Project.java:1254)
   [jasper]     at org.eclipse.ant.internal.launching.remote.InternalAntRunner.run(InternalAntRunner.java:460)
   [jasper]     at org.eclipse.ant.internal.launching.remote.InternalAntRunner.main(InternalAntRunner.java:142)
   [jasper] Caused by: org.apache.jasper.JasperException: The absolute uri: [http://java.sun.com/jsp/jstl/core] cannot be resolved in either web.xml or the jar files deployed with this application
   [jasper]     at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:55)
   [jasper]     at org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:294)
   [jasper]     at org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:81)
   [jasper]     at org.apache.jasper.compiler.TagLibraryInfoImpl.generateTldResourcePath(TagLibraryInfoImpl.java:251)
   [jasper]     at org.apache.jasper.compiler.TagLibraryInfoImpl.<init>(TagLibraryInfoImpl.java:122)
   [jasper]     at org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:431)
   [jasper]     at org.apache.jasper.compiler.Parser.parseDirective(Parser.java:489)
   [jasper]     at org.apache.jasper.compiler.Parser.parseElements(Parser.java:1445)
   [jasper]     at org.apache.jasper.compiler.Parser.parse(Parser.java:144)
   [jasper]     at org.apache.jasper.compiler.ParserController.doParse(ParserController.java:244)
   [jasper]     at org.apache.jasper.compiler.ParserController.parse(ParserController.java:105)
   [jasper]     at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:206)
   [jasper]     at org.apache.jasper.compiler.Compiler.compile(Compiler.java:386)
   [jasper]     at org.apache.jasper.JspC.processFile(JspC.java:1362)
   [jasper]     at org.apache.jasper.JspC$ProcessFile.call(JspC.java:1886)
   [jasper]     at org.apache.jasper.JspC$ProcessFile.call(JspC.java:1877)
   [jasper]     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
   [jasper]     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
   [jasper]     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
   [jasper]     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
   [jasper]     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
   [jasper]     at java.lang.Thread.run(Thread.java:748)
   [jasper] Error count: [1]

BUILD FAILED

jasper "-compile-jsp" that throws the exception (from my build.xml file)

<jasper validateXml="false" uriroot="${build.dir}/jspsrc" 
                webXmlFragment="${build.dir}/jspsrc/generated_web.xml" 
                outputDir="${build.dir}/jspjava" 
                xpoweredby="false" addwebxmlmappings="true"
                erroronusebeaninvalidclassattribute="false"
                compilersourcevm="${javac.version}" compilertargetvm="${javac.version}" />

Beginning of my WEB-INF

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
  version="4.0">

The first page that loads on the site is a consent banner (DoD website), it is here (consent.jsp) that I have the line below:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

[Edit] If I remove this line it builds successfully, is this an issue?

I am using Eclipse...

If you'd like to see something else please let me know, please send help!

Answer 1

Answering my own question, it only worked when I packaged JSTL 1.2 jar within tomcat itself in the lib folder.

Thanks