Generics: What does this entry mean?

Question

Java

What does such a record mean?
ClassName<T,A,R>
How can generic take multiple input types, what does that expand into in the code? Please provide code examples.

Answer 1

This means that three generics must be specified for this class.
For an example, look at the sources of the Map interface and/or the HashMap/LinkedHashMap/LinkedTreeMap classes. There are two generics.