code: protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
          return new FutureTask<T>(callable);
      }
docs: Returns a {@code RunnableFuture} for the given callable task.
  
  @param callable the callable task being wrapped
  @param <T> the type of the callable's result
  @return a {@code RunnableFuture} which, when run, will call the
  underlying callable and which, as a {@code Future}, will yield
  the callable's result as its result and provide for
  cancellation of the underlying task
  @since 1.6