Blog Entries

Caching pages leads to a speedier browsing experience and so is a good idea. Replacing information within a web page using Ajax similarly improves the user’s experience. The problem comes when the browser caches the information from the Ajax request. It’s a logical thing to do, but it’s not normally what the developer wants.

There are a number of ways round this. (more…)

I’m afraid that I don’t know exactly when it happened, but looking at our web-stats (produced by AWStats), the top ten browsers used to access our site are as shown below. It’s not representative of course, but it’s interesting that Firefox is so far above Internet Explorer. (more…)

In addition to having problems with JNDI not working properly, I’ve also been bashing my head against Plesk–that is supposedly “designed to simplify the management and administration of web sites”.

It’s the interaction between Plesk and Tomcat that’s the particular problem and how both of them negotiate dealing with multiple domains (or rather don’t deal with it). (more…)

I’ve recently been having difficulty getting JNDI lookup for MySQL connection pools working on our public server.

This proved very difficult to track down as all the stuff that I could find on the web said that I had to have:

• commons-dbcp-1.2.1.jar
• commons-pool-1.2.jar
• mysql-connector-java-3.1.6-bin.jar

(or the latest appropriate versions)

Unfortunately this didn’t work and my little test JSP (using the JSTL sql tags) just gave me the error: DataSource invalid:
“java.sql.SQLException: No suitable driver.

However, next I tried connecting to MySQL directly using Class.forName(""com.mysql.jdbc.Driver") and that worked. So the problem wasn’t in loading the driver. (more…)

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>