code: private void makeChoiceCache() {
  
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) JmfTr.entry(this, tc, "makeChoiceCache");
  
      choiceCache = new int[variants.length];
  
      if (map == null) {
        for (int i = 0; i < choiceCache.length; i++) {
          choiceCache[i] = -1;
        }
      }
      else {
        for (int i = 0; i < choiceCache.length; i++) {
          choiceCache[i] = map.choiceCodes[i];
        }
      }
  
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) JmfTr.exit(this, tc, "makeChoiceCache");
    }
docs: concurrency issues.