Trap in WSAD j9vm21.dll in debug mode

For a long time now, a few of my co-developers have been trying to figure out what caused this trap in WSAD:

Type=GPF vmState=0xffffffff
Target=20030915 (Windows XP 5.1 build 2600 Service Pack 2 x86)
ExceptionCode=0xc0000005 ExceptionAddress=0x1000ac84 ContextFlags=0x0001003f
Handler1=0x111016c0 Handler2=0x10019730
Module=c:\WSAD512\runtimes\base_v51\java\jre\bin\j9vm21.dll
Module_base_address=0x10000000
Offset_in_DLL=0x0000ac84
EDI=0x0011d9c8 ESI=0x008e5e60 EAX=0x74753f3e
EBX=0x0011d9c8 ECX=0x03b5cf14 EDX=0x7463656a
EBP=0x000be300 ESP=0x04381644 EIP=0x1000ac84
Generating crash dump: C:\Documents and Settings\c09974\j9.dmp

I had a quick look a while back, and couldn’t see anything obvious, and my WSAD was working OK, so I didn’t spend too much time on it Anyway, yesterday I found that I was in the same position, and the only thing that had changed on my machine was that I had installed Mercury Interactive QuickTestPro.

Not being able to have my server running in debug model with hot-swap turned on was completely unacceptable, so I spent a bit of time trying to track down what the problem was.

Tomcat 5.0 and jmx.jar in Eclipse

I used to use the sysdeo Tomcat plugin in Eclipse for my development, but someone suggested that I take a look at the Eclipse Web Tools project, which is an application server feature for Eclipse. It seems like it is the mechanism through which Eclipse is planning to support application servers in the future, so I thought it would be worth a look.

However, once I got it installed, I ran into a problem that is mentioned a few times on various sites on the web, but with few solutions. When I tried to run the application server, I got the following message:

Due to new licensing guidelines mandated by the Apache Software Foundation Board of Directors, a JMX implementation can no longer be distributed with the Apache Tomcat binaries. As a result, you must download a JMX 1.2 implementation (such as the Sun Reference Implementation) and copy the JAR containing the API and implementation of the JMX specification to: ${catalina.home}/bin/jmx.jar


This article describes the workaround that I discovered to make Tomcat 5.0 work correctly inside Eclipse.

Dynamically generating rounded corners in Java

I was looking at re-skinning a sporting team website that I had recently created, and really liked the look of the new rounded corners that grace so many websites. There are two main techniques that are used to achieve that look:

1. Having a number of 1×1 pixel divs that shape the corners
2. Having some rounded corner images

I don’t really like the first technique because it seems so inefficient (not to mention that it reminds me of the 1×1-pixel fillers of the 90’s), and the second wasn’t able to be used for my purposes because each team on my website can pick their own colour scheme from the full 24-bit RGB colour space (and I didn’t want to have to create 16777216 different corner combinations). So, what to do?

Configuring Tomcat5 and Apache2 to run with multiple instances

This describes the process for configuring Tomcat 5 on Ubuntu (or Debian) so that you can have multiple instances of Tomcat running. Typically, this would be useful when you have several domains (and/or applications) hosted on the one server and want to keep them running independantly of one another.

The general steps are based loosely on an article in LinuxJournal, however, I have added afew more explanations, corrected a couple of little inaccuracies and added new content to describe the Apache2 mechanism for loading modules and sites.