Avoid problems due to changes in JDK 1.3 introspection.
This was discovered by Phil Hanna <author@philhanna.com>
Similar to the problem with the old class attribute (changed to classname)
git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@267751 13f79535-47bb-0310-9956-ffa450edef68