Get supersuperclass type information

[chilly geode]

I have a field x. x’s type is “SomeCoolObject”. SomeCoolObject extends CoolGeneric<String>. How could I get String from the x field? (Get the generic type of x’s super’s generic.)

Normally, I would do x.getGenericSuper(), but that won’t preserve the type information if SomeCoolObject also had separate generic types. (Eg. SomeCoolObject<T> extends CoolGeneric<String>)

[remote vessel]

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[scenic bone]

Give an example of when getGenericSuperclass() isn't satisfactory for what you're asking

[chilly geode]

SomeCoolObject<T> extends CoolGeneric<String> {} (some class)

SomeCoolObject<Integer> x; (field)
((ParameterizedType)xField.getGenericType()).getActualTypeArguments()[0] -> returns Integer, rather than the desired String

((ParameterizedType)xField.getType().getGenericSuperclass()).getActualTypeArguments()[0] -> returns T, rather than String

[scenic bone]

That doesn't give T at all

[chilly geode]

according to my testing it does

[scenic bone]

Well that's against what the javadoc says should be obtained and that's against my own tests. I'd want your exact code to be sure you actually have tests that contradict all this

[chilly geode]

alright one sec

public static ArrayList<Integer> fieldTest;
    public static void main(String[] args) throws NoSuchFieldException {
        System.out.println(((ParameterizedType) Main.class.getDeclaredField("fieldTest").getType().getGenericSuperclass()).getActualTypeArguments()[0]);
    }

or if discord butchered that indenting:

[scenic bone]

That isn't even close to your original question

[chilly geode]

how so?

[scenic bone]

ArrayList isn't in any way extends Something<String>

[chilly geode]

my original question was just an example...

[chilly geode]

arraylist extends AbstractList, which is the superclass and has type params

[scenic bone]

Well your example is possible and what you're talking about now isn't. Because they're not the same

ArrayList<E> extends AbstractList<E>. It's the same E. It's not made in any way concrete

[chilly geode]

well yes, but what i'm doing is more dynamic.

I'm trying to detect the type of some field who's type is a Collection, and get the effective type of the Collection

[scenic bone]

What do you mean the effective type?

[chilly geode]

Collection<Blah> -> Blah
List<Bler> -> Bler

CoolClass extends ArrayList<Blar> {}
CoolClass -> Blar

obviously for wildcards i'll throw an error or something

[scenic bone]

Different cases -> different methods

There may exist libraries that perform that kind of analysis for you, though

[chilly geode]

ii'll look into it.

https://github.com/jhalterman/typetools
looks promising.