@Override
  public synchronized ServerLocation findServer(Set excludedServers) {
    if (PoolImpl.TEST_DURABLE_IS_NET_DOWN) {
      return null;
    }
    ServerLocation nextServer;
    int startIndex = nextServerIndex;
    do {
      nextServer = serverList.get(nextServerIndex);
      if (++nextServerIndex >= serverList.size()) {
        nextServerIndex = 0;
      }
      if (!excludedServers.contains(nextServer)) {
        return nextServer;
      }
    } while (nextServerIndex != startIndex);

    return null;
  }
A debug flag, which can be toggled by tests to disable/enable shuffling of the endpoints list
geode-core/src/main/java/org/apache/geode/cache/client/internal/ExplicitConnectionSourceImpl.java