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T: a type

C: a sub type of Collection

R: the return of comination of T and C

Example:

T = StackOverflow.class

C = List.class

R = List<StackOverflow>

How to exprime that in method signature?

It should be written like this?

<T, <C extends Collection>, R extends C<T>> HttpResponse<R> 

process(Class<T> returnType, Class<C> parametrizedReturnType)

I know C<T> does not work.

In order to do

List<StackOverflow> res = process(StackOverflow.class, List.class)

Any ideas?

In order to avoid the issues with raw types (etc) you can pass in something like a "prototype" object:

<T, C extends Collection<T>> HttpResponse<C> process(C prototype) {

  ...

}

So you can invoke this like:

HttpResponse<List<String>> response = process(new ArrayList<>());

The nature of the prototype object depends upon what you need to do with it in the process method. Perhaps you can accept an empty list; perhaps you would need to pass in a supplier of an instance, for example:

<T, C extends Collection<T>> HttpResponse<C> process(Supplier<C> supplier) {

  return new HttpResponse<>(supplier.get());

}



HttpResponse<List<String>> response = process(ArrayList::new);