Apache Maven 3 is required to build Apache Commons Weaver. Things to know:
Commons Weaver provides a Maven plugin as one of its submodules; the plugin is itself required by the modules which demonstrate the provided “weaver modules.” This means that Commons Weaver requires, at minimum, the package phase to be specified when building the project. This makes the various modules visible to one another using the Maven reactor, detailed here. Without installing to your local Maven repository, however, certain items will always fail; e.g. mvn clean without package, mvn dependency:list, mvn dependency:tree, and probably others. In general, mvn install will avoid further surprises down the line.
The Privilizer is the fundamental “guinea pig” weaver module. Since the whole point of the Privilizer relates to Java security, it is only natural that its tests be executable with Java security enabled. It is also reasonable to test without security enabled, to show that your code works as always. The example and ant/test modules each have a sec profile defined; You can run their tests with this profile enabled to turn on Java security.
Located at ant/test, this module's tests are implemented by unpacking the source of the example module and reusing it. For this reason, the example module must have been packaged previously to executing the ant/test tests, so in a multimodule build you should at least specify the package phase of the default lifecycle. Alternatively, you can disable this module's tests by deactivating the profile in which they are set up: antlib-test.
Similarly, when building the project site you should deactivate the antlib-test profile, to stop this module's tests from requiring the example module to have been previously packaged.