Why does ternary operator fail with a type mismatch error?

Question

I have the following simple code piece:

List<XXXXBean> queryPeriodData()
{
    if (CollectionUtils.isEmpty(res))
    {
        return Collections.emptyList();
    }

    return res;
}

It works.

but if I change to this, there is a compile error...

return CollectionUtils.isEmpty(res) ? Collections.emptyList() : res;

error message is

I don't know the difference between the two way.

Answer 1

在语句中尝试Collections.<XXXXBean>emptyList()