code: protected static Boolean parseOptionalBooleanValue(JSONObject json, String key) {
  
          try {
              return Boolean.valueOf(json.getBoolean(key));
          } catch (JSONException e) {
              LOG.info(Messages.get().getBundle().key(Messages.LOG_OPTIONAL_BOOLEAN_MISSING_1, key), e);
              return null;
          }
      }
docs: Helper for reading an optional Boolean value - returning <code>null</code> if parsing fails.
  @param json The JSON object where the value should be read from.
  @param key The key of the value to read.
  @return The value from the JSON, or <code>null</code> if the value does not exist, or is no Boolean.