从getDeclaredMethods查找具有实际类型的通用方法

Question

I have generic classes that look like:

interface X<Input, Output>
{
  Output process(Input input);
}

class Y implements X<Integer, Float> 
{   
  Float process(Integer input); 
}

I use getDeclaredMethods to find process on Y just with its name (not the arguments, on purpose). When I look at the return Method[], process shows up twice, with Input=Object, Output=Object, and then with the actual instantiation types: Integer and Float.

Please note: I can see 1 function with Object,Object in the Method[] AND 1 function with the actual types I use to instantiate, like Integer,Float. So, the second function, which I'm interested in, is accessible from Method[].

What is the best way to get only the method with the actual types?

Answer 1

and then with the actual instantiation types.

That's not possible. You should see a single method whose parameter types are Object . You can also look at the method's generic parameter and return types, and you will find that they are both type variables ( Input and Output are type variables).

Subclasses of this class that inherit from it with specific type arguments for the type parameters, will have two methods: a method with the more specific parameter and return types, and a bridge method , with the original class's method's parameter and return types, in order to override it. If you are asking how to ignore the bridge method, simply check if it's a bridge method ( .isBridge() )

Answer 2

Generic types are known only at compilation time. Object is the actual type of generics at runtime, so you can't get them while running the program.