@Test public void rocksLikeACarriage() { Assert.assertEquals("... from side to side", new MusicalCarriage().rock()); }
@Override public String rock() { return Carriage.super.rock(); }
MusicalCarriage implements Carriage, Jukebox { @Override public String rock() { return Carriage.super.rock(); } }
MusicalCarriage implements Carriage, Jukebox { @Override public String rock() { return Carriage.super.rock(); }  }
MusicalCarriage implements Carriage, Jukebox { @Override public String rock() { return Carriage.super.rock(); }  @Override String rock(); }
MusicalCarriage implements Carriage, Jukebox { @Override public String rock() { return Carriage.super.rock(); }  @Override String rock();  }