There were two build errors...
The first (per the subject of the bug) is fixed by adding a build (and I
assume run-time) dependency on libcommons-collections-java
The second (a few lines later in the build output) is due to ant.properties
calling out the version of jsp.jar that is provided by libservlet2.5-java,
whereas the debian/control specified a dependency on only
libservlet3.0-java. I fixed this by calling out version 2.2 rather than
2.1 in ant.properties (assuming the intention was to change from
libservlet2.5 to libservlet3.0).
This is the maintainer address of Debian's Java team
debian-j...@lists.debian.org for discussions and questions.