Can not implement JSTL with new classpath

I have a big problem to implement my jsp pages.

I'm using Spring 4 with theoretically JSTL 1.2 + Servlet 3.0 in STS (Eclipse Luna) - Tomcat 7. I saw the article posted here, however I could not solve.

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

This url is recognized by the STS IDE (Eclipse). However when I try to open the page displays the error:

/views/root/index.jsp(1,63) PWC6188: 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

src/main/webapp/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<flow xmlns="http://www.springframework.org/schema/webflow"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/webflow
        http://www.springframework.org/schema/webflow/spring-webflow-2.0.xsd">

    <view-state id="start">
    </view-state>

</flow>

src/main/webapp/WEB-INF/lib

javax.servlet.jsp.jstl-1.2.1.jar
javax.servlet.jsp.jstl-api-1.2.1.jar

Trying with another approach:

<%@ taglib prefix="c" uri="http://xmlns.jcp.org/jsp/jstl/core" %>

This url is not recognized by the Eclipse IDE. Accusing error in project.

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:c="http://java.sun.com/jsp/jstl/core">

As some libs who put in pom.xml (maven) the url in that line is recognized, however nothing happens in the browser.

PS: Spring in all four projects say they no longer need the file "web.xml" and try to put some tutorials to follow, again accuses the eclipse error.

Solution

After 35 hours of work, I discovered that the error is conflict with more than one library "Servlet" e "JSTL".

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