title: Eclipse project window shows error but code editor shows no error
body: <p>For my jsp file, the code editor shows no error, but the projects window shows an error. I built my project again, cleaned the project, restart eclipse twice and summoned cthulhu. But my project still shows an error. How do I find the cause and fix the problem ?</p>
  
  <p><strong>Eclipse project -</strong> </p>
  
  <p><img src="https://i.stack.imgur.com/I5dUi.jpg" alt="enter image description here"></p>
  
  <p><strong>JSP file -</strong> </p>
  
  <pre><code>&lt;%@ page language="java" contentType="text/html; charset=ISO-8859-1"
      pageEncoding="ISO-8859-1"%&gt;    
  &lt;!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"&gt;
  
  &lt;%@ taglib prefix="mine" uri="DiceFunctions"%&gt;
  
  &lt;html&gt;
  &lt;head&gt;
  &lt;meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"&gt;
  &lt;/head&gt;
  &lt;body&gt;
  
  ${mine:rollIt()}
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p><strong>TLD file -</strong> </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="ISO-8859-1" ?&gt;
  
  &lt;taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" version="2.0"&gt;
  &lt;tlib-version&gt;1.2&lt;/tlib-version&gt;
  
  &lt;uri&gt;DiceFunctions&lt;/uri&gt;
  &lt;function&gt;
  &lt;name&gt;rollIt&lt;/name&gt;
  &lt;function-class&gt;foo.DiceRoller&lt;/function-class&gt;
  &lt;function-signature&gt;
  int rollDice()
  &lt;/function-signature&gt;
  &lt;/function&gt;
  &lt;/taglib&gt;
  </code></pre>
  
  <p>Note - look at my project structure. Make a folder foo under web-inf/classes and put the dice class file inside foo. Otherwise the project won't work.</p>