Java Generics (Wildcards)

Question

I have a couple of questions about generic wildcards in Java:

1. What is the difference between List and List

Answer 1

Josh Bloch also has a good explanation of when to use super and extends in this google io video talk where he mentions the Producer extends Consumer super mnemonic.

From the presentation slides:

Suppose you want to add bulk methods to Stack

void pushAll(Collection src);

– src is an E producer

void popAll(Collection dst);

– dst is an E consumer