I am running Hudson under Tomcat 5.5 with Java 1.5, building a single-module
Maven project. Since version 5.5 of Tomcat, it can be run with a JRE rather than
a JDK, as Tomcat comes bundled with the Java compiler from Eclipse.

Initially, I ran into problems compiling Java because, with the default
settings, it seemed to be using the JRE running Tomcat, which of course doesn't
have tools.jar. I then setup a JDK properly in Hudson, ensured that the project
was configured to use it, and tried again. It seemed to completely ignore this
setting and continued using the same JRE. I tried re-starting, but that had no
effect.

The only way I got this to work was to start Tomcat using a JDK - it appeared
that the JDK settings in Hudson were ignored.

Thanks, Alex.