When you use the same doclet task twice (in a build.xml file,
or 'embedded'), SubTasks shared between the two definitions
will always be the same. I.e.:

<target>

  <!-- will create sessoin beans in dir A. -->
  <ejbdoclet destDir="A">
    <session/>
  </ejbdoclet>


  <!-- will create session beans in dir A also! -->

  <ejbdoclet destDir="B">
    <session/>
  </ejbdoclet>

  <!-- will create session beans in dir C -->
  <ejbdoclet destDir="C">
    <session destDir="C"/>
  </ejbdoclet>

SubTask.init() checks for null values (for destDir e.a.).
If they're null, it inherits them from the parent DocletTask.

If they're not null (the second time it gets called), they don't
get reconfigured.

Having a flag in SubTask doesn't solve this - the subtaskmap should
be reset, so all fields are properly reconfigured, or after execute
is finished, the fields should be set to null.

I know there are some related issues that are solved too by this.