Question

Why can’t i have classcastexception?
E means C in the example, doesn’t it?
B is not C, I thought my cast must work only for compiler.
Where is my mistake?

public class A{
public static void main(String...s){
    Monitor<C> m = new Monitor<C>(); 
    C arg2 = new C();
    B d = m.f(arg2);
    System.out.println(d);
    }
}
class B extends A{}
class C extends B{}
class Monitor<E extends B>{
public E f(E E){
    return (E) new B();//Why this place didn't give me ClassCastException?
}
}

Answer 1

This is because of type erasure in generics. Since you have generic type <E extends B> statement return (E) new B() is compiled into return (B) new B() so you have not got ClassCastException.