Revision history [back]

There could be a few reasons why IntelliJ IDEA is unable to recognize the symbol "c:out" when utilizing JSTL 3.0. Here are some potential solutions:

1. Make sure that the jstl.jar file is included in your project's classpath. You can check this by going to "Project Structure" -> "Libraries" and ensuring that jstl.jar is listed.

2. Check that the JSTL version in your project matches the version that IntelliJ IDEA is set up to recognize. You can do this by going to "Settings" -> "Languages & Frameworks" -> "JSTL" and selecting the appropriate version.

3. Ensure that the JSTL namespace is properly declared in the JSP page, like so: <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

4. Check that there are no syntax errors or other issues in your JSP page that might be causing IntelliJ IDEA to fail to recognize the "c:out" symbol.

If none of these solutions work, it may be worth consulting the IntelliJ IDEA documentation or seeking assistance from the IntelliJ IDEA community.