Class with 2 methods: generic argument vs primitive argument

Question

Suppose you have the following Java class:

public class MyClass<T>{
    public void myMethod(int idx){...}
    public void myMethod(T idx){...}
}

Now if a class user does:

MyClass<Integer> ref = new MyClass<>();
ref.myMethod(1); // void myMethod(int idx) gets called
ref.myMethod(new Integer(1)); // void myMethod(T idx) gets called

Why does ref.myMethod(1) not call the generic method? Which checks are in place?

Thanks