We have similar pattern in {instanceKlass, typeArrayKlass, objArrayKlass, etc}.hpp::

  static ObjArrayKlass* cast(Klass* k) {
    return const_cast<ObjArrayKlass*>(cast(const_cast<const Klass*>(k)));
  }
  static const ObjArrayKlass* cast(const Klass* k) {
    assert(k->is_objArray_klass(), "cast to ObjArrayKlass");
    return static_cast<const ObjArrayKlass*>(k);
  }

Seeing the word "cast" three times on a single line is confusing.

Proposed cleanup:

  template <typename O, typename K>
  static O* cast_impl(K* k) {
    assert(k->is_objArray_klass(), "cast to ObjArrayKlass");
    return static_cast<O*>(k);
  }

 static ObjArrayKlass* cast(Klass* k) {
    return cast_impl<ObjArrayKlass>(k);
  }

  static const ObjArrayKlass* cast(const Klass* k) {
    return cast_impl<const ObjArrayKlass>(k);
  }