Examination of the source code shows that there are potential memory leaks in windows XP specific code when handling NetworkInterfaces.
e.g.:
ptr = getAdapter(env, index);
if (ptr != NULL && (ptr->Flags & IP_ADAPTER_NO_MULTICAST)) {
  val = JNI_FALSE;
  free(ptr);
}

Obviously that pointer should be freed no matter the value of ptr->Flags