Shulou(Shulou.com)05/31 Report--

This article mainly explains "what are extendsT and superT in Java". Interested friends might as well take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what are extendsT and superT in Java?"

? Wildcard type

The difference between a type parameter and a type parameter is that all T represents the same type for the compiler. For example, in the following generic method, all three T refer to the same type, either String or Integer.

Public List fill (T... T)

But wildcards do not have this constraint, List simply means: there is something in the collection, I don't know what it is.

So that's the mistake here, List.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.