Java Generics - Casting to "null's class"

[Bob Hunt]

Hi,

I came across an interesting situation.
I've got a method that gets a class as a parameter so the caller method doesn't have to cast, because the called method will have the same return type as the class parameter's type. Here is a simplified version of that.

public static void main(String[] args) {
	System.out.println(test(Integer.class, 10));
}

private static <T> T test(Class<T> c, Integer i) {
              return (T)i;
}

When I pass

Integer.class

I get 10. When I pass "null" I still get 10. When I write

 return (null)i

I get a compiler error, of course.

My question: What happens when I pass null as a class and the JVM try to cast 10 to null in runtime?

[Greg Charles]

I don't really know how Java handles null in that case, but I do know it's not at run time. In Java, both casting and generics are seen by the compiler only. They have no effect on the running program.