code: public Properties loadProperties(ConfigurationManager configurationManager, String handlerPrefix) {
          PropertyOperations allproperties = properties(configurationManager.getAllProperties());
  
          PropertyOperations handlerProps = allproperties.filterByAndRemoveKeyPrefix(handlerPrefix + ".");
          return handlerProps.loadProperties();
      }
docs: Get all properties for a simple handler which takes only properties prefixed with handler name:
  
  myHandler.property1=val
  myHandler.property2=val