code: public void enterTransactionState(Event event) {
  		ChaincodeMessage message = messageHelper(event);
  		logger.debug(String.format("[%s]Received %s, invoking transaction on chaincode(src:%s, dst:%s)",
  				shortID(message), message.getType().toString(), event.src, event.dst));
  		if (message.getType() == TRANSACTION) {
  			// Call the chaincode's Run function to invoke transaction
  			handleTransaction(message);
  		}
  	}
docs: enterTransactionState will execute chaincode's Run if coming from a TRANSACTION event.