code: public Boolean getBooleanProperty(String key, Boolean defaultValue) {
          String val = getProperty(key, defaultValue.toString());
          Boolean booleanVal = Boolean.parseBoolean(val);
          return booleanVal;
      }
docs: Gets a boolean property with a boolean value.
  @param key The key string.
  @param defaultValue The default value.
  @return The boolean property value.