Surprise with Groovy null safe dereferencing operator '?' . . .

It's been a surprise for me learning that the first() method to access the first element of a List in groovy throws an exception on an empty list even with a null-safe dereferencing operator:

//when List is null def pList = null assert 'null/empty' == pList ? 'not null/empty' : 'null/empty' assert null == pList?.size() assert null == pList?.first()?.toString() try{ println pList[0]?.toString() } catch(all){ assert true assert all in NullPointerException } //when List is empty pList = [] assert 'null/empty' == pList ? 'not null/empty' : 'null/empty' assert 0 == pList?.size() assert null == pList[0]?.toString() try{ pList?.first()?.toString() } catch(all){ assert true assert all in NoSuchElementException } //when list is not empty pList = [1,2,3,4] assert 'not null/empty' == pList ? 'not null/empty' : 'null/empty' assert 4 == pList?.size() assert '1' == pList[0]?.toString() assert '1' == pList?.first()?.toString()