How to capture variable parameters with Mockito?

Mockito 1.10.5 has introduced this feature.

For the code sample in the question, here is one way to capture the varargs:

    ArgumentCaptor<String> varArgs = ArgumentCaptor.forClass(String.class);
    A mock = Mockito.mock(A.class);
    mock.setNames("Jeff", "Mike", "John");
    Mockito.verify(mock).setNames(varArgs.capture());

    //Results may be validated thus:
    List<String> expected = Arrays.asList("Jeff", "Mike", "John");
    assertEquals(expected, varArgs.getAllValues());

Please see the ArgumentCaptor javadoc for details.