code: private synchronized void loadLookup() {
          if (lookup != null)
              return;
  
          Object[][] contents = getContents();
          HashMap<String,Object> temp = new HashMap<>(contents.length);
          for (int i = 0; i < contents.length; ++i) {
              // key must be non-null String, value must be non-null
              String key = (String) contents[i][0];
              Object value = contents[i][1];
              if (key == null || value == null) {
                  throw new NullPointerException();
              }
              temp.put(key, value);
          }
          lookup = temp;
      }
docs: We lazily load the lookup hashtable.  This function does the
  loading.