Tag Archives: JSP

JasperException: Failed to load or instantiate TagExtraInfo

org.apache.jasper.JasperException: Failed to load or instantiate TagExtraInfo class

(I had to shorten the article title to fit!)

I’ve just had a problem when I’ve taken a web application from my local Tomcat 5.5 development server (where it worked fine) and uploaded it onto a public server (also using Tomcat 5.5).

Continue reading JasperException: Failed to load or instantiate TagExtraInfo

Outputting stack traces in a JSP using JSTL

If you’re writing a JSP using the JSTL tag <c:catch var=”myError”> … </c:catch> then I’m sure that you know that the next thing to do is to check after the closing catch tag to see if myError is empty. If not you can output some useful error message having successfully caught any exception. However, sometimes it’s useful to actually output the stack trace (when debugging a site for example). It turns out not to be difficult to do this. Simply copy in the following:

<c:if test="${not empty myError}">
<p class="error">An error occured: <c:out value="${myError}"/></p>
<pre>
<c:forEach var="stackTraceElem" items="${myError.stackTrace}">
<c:out value="${stackTraceElem}"/><br/>
</c:forEach>