Scala / PowerMockito - Java final classes causing build error in Scala Tests using Powermockito

Question

I have a final class:

public final class AClass {
    private final AConfig aClassConfig;
    public final static BeanName = "aClass"
}

and I'm trying to mock it in tests:

@RunWith(classOf[PowerMockRunner])
@PrepareForTest(Array(classOf[AClass]))
class AClassTests extends FunSuite {
    test("mock final class test") {
        val aClass = PowerMockito.mock(classOf[AClass])
        assert(aClass != null)
    }
}

This causes the error:

Cannot subclass final class class com.me.AClass
java.lang.IllegalArgumentException: Cannot subclass final class class com.me.AClass

I've followed multiple tutorials on how these tests should be set up and as far as I can tell the error is due to @PrepareForTest(...) not running properly, but that's just a guess.