There are presently several unchecked C-style downcasts to classes in the CollectorPolicy hierarchy. All of these appear to be unnecessary, and could be replaced using existing mechanisms that provide checkable conversions.

There are also a couple of explicit C-style upcasts to CollectorPolicy* that should be unnecessary. One of them can simply be removed. The other (in G1CollectedHeap::collector_policy) is problematic, as the source class (G1CollectorPolicy) is incomplete in this context. This could result in the explicit cast being treated as a reinterpret_cast, which would be wrong. Alternatively, we could end up with an ODR violation.

Note that there don't appear to be any explicit C++ style casts involving this hierarchy.