### Question:
RunnableCallable implements Callable<Void>, Runnable { @Override public void run() { if (runnable != null) { runnable.run(); } else { try { callable.call(); } catch (Exception ex) { throw new RuntimeException(ex); } } } RunnableCallable(Runnable runnable);  RunnableCallable(Callable<?> callable); @Override Void call(); @Override void run(); String toString();  }### Answer:
@Test(expected = RuntimeException.class) public void callableExRun() throws Exception { CEx c = new CEx(); RunnableCallable rc = new RunnableCallable(c); rc.run(); }