public String getStreamSerdeName(String systemName, String streamName) {
    StreamConfig streamConfig =  new StreamConfig(this);
    Optional<String> option = streamConfig.getStreamMsgSerde(new SystemStream(systemName, streamName));
    return option.isPresent() ? option.get() : null;
  }
Get the class name according to the serde name.

@param name serde name
@return serde factory name, or null if there is no factory defined for the
        supplied serde name.
samza-log4j2/src/main/java/org/apache/samza/config/Log4jSystemConfig.java