Java

Is Groovy a good way to pass complex data from one server to another (instead of JSON or XML)?
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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).

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We have several web applications derived from the same code base and as well as sharing the jars in WEB-INF/lib, we provide set of administration pages to allow users to configure and administer the applications. Until now, we’ve always had to make copies of the admin pages and this has caused us configuration headaches as we try and make sure that all the applications have the latest versions of all the pages.

But now I’ve finally managed to work out how to make Tomcat follow symbolic links—and it’s very easy! (more…)

This article describes how we used Groovy to create a DSL for the clauses in a rules engine. We have been collaborating in the development of an “expert system” application for KnowledgeBench Ltd. This application uses a forward chaining rules engine to provide a “smart” system capable of creating formulations in domains such as pharmaceutical tablet formulation, inhalers, paints, food & drink and cosmetics. (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…)