/**
   * @param nodeId Primary node ID.
   * @param req Request.
   * @return Remote transaction.
   * @throws GridException If failed.
   * @throws GridDistributedLockCancelledException If lock has been cancelled.
   */
  @SuppressWarnings({"RedundantTypeArguments"})
  @Nullable
  public GridNearTxRemote<K, V> startRemoteTxForFinish(
      UUID nodeId, GridDhtTxFinishRequest<K, V> req)
      throws GridException, GridDistributedLockCancelledException {
    GridNearTxRemote<K, V> tx = null;

    ClassLoader ldr = ctx.deploy().globalLoader();

    if (ldr != null) {
      for (GridCacheTxEntry<K, V> txEntry : req.nearWrites()) {
        GridDistributedCacheEntry<K, V> entry = null;

        while (true) {
          try {
            entry = peekExx(txEntry.key());

            if (entry != null) {
              entry.keyBytes(txEntry.keyBytes());

              // Handle implicit locks for pessimistic transactions.
              tx = ctx.tm().tx(req.version());

              if (tx != null) {
                if (tx.local()) return null;

                if (tx.markFinalizing()) tx.addWrite(txEntry.key(), txEntry.keyBytes());
                else return null;
              } else {
                tx =
                    new GridNearTxRemote<K, V>(
                        nodeId,
                        req.nearNodeId(),
                        req.threadId(),
                        req.version(),
                        null,
                        PESSIMISTIC,
                        req.isolation(),
                        req.isInvalidate(),
                        0,
                        txEntry.key(),
                        txEntry.keyBytes(),
                        txEntry.value(),
                        txEntry.valueBytes(),
                        ctx);

                if (tx.empty()) return tx;

                tx = ctx.tm().onCreated(tx);

                if (tx == null || !ctx.tm().onStarted(tx))
                  throw new GridCacheTxRollbackException(
                      "Failed to acquire lock "
                          + "(transaction has been completed): "
                          + req.version());

                if (!tx.markFinalizing()) return null;
              }

              // Add remote candidate before reordering.
              if (txEntry.explicitVersion() == null)
                entry.addRemote(
                    req.nearNodeId(),
                    nodeId,
                    req.threadId(),
                    req.version(),
                    0,
                    tx.ec(),
                    /*tx*/ true,
                    tx.implicitSingle());

              // Remote candidates for ordered lock queuing.
              entry.addRemoteCandidates(
                  Collections.<GridCacheMvccCandidate<K>>emptyList(),
                  req.version(),
                  req.committedVersions(),
                  req.rolledbackVersions());
            }

            // Double-check in case if sender node left the grid.
            if (ctx.discovery().node(req.nearNodeId()) == null) {
              if (log.isDebugEnabled())
                log.debug("Node requesting lock left grid (lock request will be ignored): " + req);

              if (tx != null) tx.rollback();

              return null;
            }

            // Entry is legit.
            break;
          } catch (GridCacheEntryRemovedException ignored) {
            assert entry.obsoleteVersion() != null
                : "Obsolete flag not set on removed entry: " + entry;

            if (log.isDebugEnabled())
              log.debug("Received entry removed exception (will retry on renewed entry): " + entry);

            if (tx != null) {
              tx.clearEntry(entry.key());

              if (log.isDebugEnabled())
                log.debug(
                    "Cleared removed entry from remote transaction (will retry) [entry="
                        + entry
                        + ", tx="
                        + tx
                        + ']');
            }
          }
        }
      }
    } else {
      String err = "Failed to acquire deployment class loader for message: " + req;

      U.warn(log, err);

      throw new GridException(err);
    }

    return tx;
  }