Advice

I was reading about Generics from the Eleventh Edition of "Java The Complete Reference", specifically the "Run-Time type Comparisons with a Generic Hierarchy" part.

I was confused by this part:

// The following can't be compiled because
// generic type info does not exist at run time.
// if (iOb2 instanceof Gen2<Integer>)
//   System.out.println("iOb2 is instance of Gen2<Integer>")

But when I tried to run the code myself it compiled and executed perfectly:

class Gen<T>{}

class Gen2<T> extends Gen<T>{}

public class Tester{
    public static void main(String[] args){
        
        Gen2<Integer> obj = new Gen2<Integer>();
        System.out.println(obj instanceof Gen2<Integer>);
        //output is true

    }
}

Now I understand that Type Erasure should cause a compile time error. But I don't understand why my code works.

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