When I'm trying to override a task that is provided from plugin I got a "a task with that name already exists" exception.
I'm not sure if it's expected behavior and if not whose part this is (plugin vendor or gradle) but I think gradle could mediate this.

The behavior is rather strange since the overriden logic seems to work (println writes data to console).

I tried doing the following:

...
apply plugin: 'gradlefx'

task compile(overwrite: true)

...

I'm not that into gradle internals but with little thinking I figured out that the problem may not be in my override but rather in plugin trying to inject it's own tasks with the same name.

The workaround that helped me is the following:

...
apply plugin: 'gradlefx'

afterEvaluate {
task compile(overwrite: true)

}
...

Maybe all task overrides should happen after evaluation or I'm missing something?

P.S.
Javadoc for TaskContainer is rather confusing, since the description does mention override option, whereas overwrite is expected.