@Override
  public void cmdExecute(final @NotNull Message clientMessage,
      final @NotNull ServerConnection serverConnection,
      final @NotNull SecurityService securityService, long start)
      throws IOException, ClassNotFoundException, InterruptedException {
    serverConnection.setAsTrue(REQUIRES_RESPONSE);
    TXManagerImpl txMgr = (TXManagerImpl) serverConnection.getCache().getCacheTransactionManager();
    InternalDistributedMember client =
        (InternalDistributedMember) serverConnection.getProxyID().getDistributedMember();
    int uniqId = clientMessage.getTransactionId();
    TXId txId = new TXId(client, uniqId);
    if (txMgr.isHostedTxRecentlyCompleted(txId)) {
      if (logger.isDebugEnabled()) {
        logger.debug("TX: found a recently rolled back tx: {}", txId);
        sendRollbackReply(clientMessage, serverConnection);
        txMgr.removeHostedTXState(txId);
        return;
      }
    }
    final TXStateProxy txState = txMgr.getTXState();
    try {
      if (txState != null) {
        txId = txState.getTxId();
        txMgr.rollback();
        sendRollbackReply(clientMessage, serverConnection);
      } else {
        // could not find TxState in the host server.
        // Protect against a failover command received so late,
        // and it is removed from the failoverMap due to capacity.
        sendRollbackReply(clientMessage, serverConnection);
      }
    } catch (Exception e) {
      writeException(clientMessage, e, false, serverConnection);
      serverConnection.setAsTrue(RESPONDED);
    } finally {
      if (logger.isDebugEnabled()) {
        logger.debug("TX: removing tx state for {}", txId);
      }
      if (txId != null) {
        TXStateProxy proxy = txMgr.removeHostedTXState(txId);
        if (logger.isDebugEnabled()) {
          logger.debug("TX: removed tx state proxy {}", proxy);
        }
      }
    }
  }
Command for performing Rollback on the server
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/command/RollbackCommand.java