Java – Eclipse “cannot find the tag library descriptor” for custom tags (not JSTL!)

custom-tagseclipsejavajsptaglib

I have a Java EE project which build fine with Ant, deploys perfectly to JBoss, and runs without any trouble. This project includes a few custom tag libraries (which is not JSTL!), which are also working without any difficulties.

The problem is with the Eclipse IDE (Ganymede): in every single JSP file which uses our custom tags, the JSP parser flags the taglib include line with with this error:

Cannot find the tag library descriptor for (example).tld

This also causes every use of the tab library to be flagged as an error, and since the IDE doesn't have their definition, it can't check tag parameters, etc.

Our perfectly-working JSP files are a sea of red errors, and my eyes are beginning to burn.

How can I simply tell Eclipse, "The tag library descriptor you are looking for is "src/web/WEB-INF/(example)-taglib/(example).tld"?

I've already asked this question on the Eclipse support forums, with no helpful results.

Best Answer

In Eclipse Helios "Java EE Module Dependencies" in the project properties has been replaced with "Deployment Assembly".

So for solving this problem with Eclipse Helios, the way I did it is the following:

Right click on the project in package explorer and choose "Import..."
Accept the default selection "File System" and press "Next"
Press "Browse" in the From directory line, go to your tomcat installation and locate the file webapps/examples/WEB-INF/lib (I have tomcat 6, other versions of Tomcat may have the path webapps/jsp-examples/WEB-INF/lib). Once in the path press OK.
Click besides jstl.jar and standard.jar to activate the check boxes
On the line Into folder click on Browse and choose the library folder. I use /lib inside the project.
Click "Finish"
Right click on the project in Package Explorer view and choose properties (or press Alt + Enter)
Click on "Java Build Path"
Click "Add Jar", click on your project, folder lib, select jstl.jar, press OK
Click "Add Jar", click on your project, folder lib, select standard.jar, press OK
Press OK to dismiss the properties dialog
Click on the Problems view and select the message "Classpath entry .../jstl.jar will not be exported or published. Runtime ClassNotFoundExceptions may result.".
Right click on it and select "Quick Fix".
Accept the default "Mark the associated raw classpath entry as a publish/export dependency" and press Finish.
Do the same for standard.jar

This solves the problem, but if you want to check what has happened in "Deployment Assembly", open the project properties again, select "Deployment Assembly" and you'll see that standard.jar and jstl.jar have been added to WEB-INF/lib folder.

Related Solutions

Jsp – JSTL Tomcat 6.0 Cannot find the taglib descriptor Error

To use tag libraries you need to add standard.jar and jstl.jar and add to your buildpath

get the jars from http://jstl.java.net/

Java – Can not find the tag library descriptor for “http://java.sun.com/jsp/jstl/core”

Can not find the tag library descriptor for “http://java.sun.com/jsp/jstl/core”

Based on one of your previous questions you're using Tomcat 7. In that case you need JSTL 1.2. However, you've there a jstl.jar file while JSTL 1.2 has clearly the version number included like so jstl-1.2.jar. The sole filename jstl.jar is typical for JSTL 1.0 and 1.1. This version requires a standard.jar along in /WEB-INF/lib which contains the necessary TLD files. However, in your particular case the standard.jar is clearly missing in /WEB-INF/lib and that's exactly the reason why the taglib URI couldn't be resolved.

To solve this you must remove the wrong JAR file, download jstl-1.2.jar and drop it in its entirety in /WEB-INF/lib. That's all. You do not need to extract it nor to fiddle in project's Build Path.

Don't forget to remove that loose c.tld file too. It absolutely doesn't belong there. This is indeed instructed in some poor tutorials or answers elsewhere in the Internet. This is a myth caused by a major misunderstanding and misconfiguration. There is never a need to have a loose JSTL TLD file in the classpath, also not in previous JSTL versions.

In case you're using Maven, use the below coordinate:

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>

You should also make sure that your web.xml is declared conform at least Servlet 2.4 and thus not as Servlet 2.3 or older. Otherwise EL expressions inside JSTL tags would in turn fail to work. Pick the highest version matching your target container and make sure that you don't have a <!DOCTYPE> anywhere in your web.xml. Here's a Servlet 3.0 (Tomcat 7) compatible example:

<?xml version="1.0" encoding="UTF-8"?>
<web-app
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">

    <!-- Config here. -->

</web-app>

###See also:

Our JSTL wiki page (you can reach there by hovering the mouse on jstl and clicking info link)
How to install JSTL? The absolute uri: http://java.sun.com/jstl/core cannot be resolved

Best Answer

Related Solutions

Jsp – JSTL Tomcat 6.0 Cannot find the taglib descriptor Error

Java – Can not find the tag library descriptor for “http://java.sun.com/jsp/jstl/core”

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