Need help about wildcard generic types in Java

Question

I am learning generic programming in java. I saw these charts in Core Java (Edition 9):

And I saw these charts in Introduction to Java Programming Comprehensive Version Tenth Edition:

But I believe it should be this instead:

Could someone tell me whether I am right?

Thanks a lot. The question is updated. Could you please advise me again? — cmpltrtok, Aug 30 '20 at 08:24
Sorry, Sweeper. This is my first post in stackoverflow. I have already created a new post here: https://stackoverflow.com/questions/63655638/why-cant-i-put-an-object-of-superclass-of-b-into-container-super-b — cmpltrtok, Aug 30 '20 at 08:51

score 3 · Accepted Answer · answered Aug 30 '20 at 05:46

3

Yes, you are correct. The mistake is listed in the Errata for this edition (which might be useful for similar confirmations in the future):

Chapter 19

Page 749, Figure 19.6, change the last "A<B' subclass>" to "A<B' superclass>".

answered Aug 30 '20 at 05:46

Mark Peters

score 0 · Answer 2 · edited Aug 31 '20 at 12:15

0

Yes, it should change from A<B' s subclass> to A<B' s superclass>.

edited Aug 31 '20 at 12:15

Mario Codes

answered Aug 30 '20 at 06:51

2 Answers2