Re: Objects that can't be garbage collected?

I got a weird question in a phone interview the other day that I'm not
sure what to make of.

The question was "What object(s) cannot be garbage collected?" I asked
for a little clarification, and he said "What objects, if collected,
would cause problems [in the JVM]?"

Hmmmm... still not sure if 1) I accurately understood what he was
asking 2) It's a perfectly good question that I don't know the answer
to, or 3) it was a trick question

If it's #2, hopefully someone will fill me in.

My first thoughts were that this must be a theoretical question, b/c
if there were such a situation where an object is collected before
it's safe to do so, then it would be a pretty big bug in the JVM
implementation.

Going for the theoretical angle, my thoughts were that something like
a ClassLoader object could be the answer. Let's say that somehow, I
managed to erase the reference from Foo to the FooClassLoader that
loaded it , and that it is collected before an instance of Foo calls a
method that uses an instance of Foo2 (assume that Foo and Foo2 are
from a library that only FooClassLoader has access to.) We'd have a
something like a ClassNotFoundException from the bootstrap CL,
correct? As far as the "realisticalness" of the situation, it seems
like the ability to manipulate a class's ClassLoader field would
violate the security model. Then again, if the reference in Foo to
its class loader is simply a regular private member, then Foo could
set the reference to null in its constructor or some other point,
correct?

Am I missing something obvious, or is this a weird question?