泛型混淆中的类型擦除

Question

I was reading concept of type erasure in generics. While executing the below piece of code I got confused.

public class CollectionsWild {
    void Test(Collection<?> t){
        System.out.println("Collection");
    }

    void Test(List<Integer> t){
        System.out.println("List");
    }


    public static void main(String[] args) {
        CollectionsWild o = new CollectionsWild();
        o.Test(new ArrayList<String>());
    }

}

As per the type erasure concept, " List<Integer> t " is converted to "List t" in bytecode. So why is my method test called which is having Collection as the parameter. It should have called the method with List as parameter

Answer 1

This is nothing to do with erasure. Overload resolution is done at compile time. Only one overload matches ArrayList<String> and that is the one that is chosen. If there was more than one match, the most specific would have been selected.

In the case that of overloading with the same type erasure, the definition of the type does not compile before overload resolution is even considered.

Answer 2

Method selection is a compile-time thing. Type erasure happens afterward . As you can see in JLS§15.12.2 , generic type parameters are considered:

Deciding whether a method is applicable will, in the case of generic methods (§8.4.4), require an analysis of the type arguments.