code: public int getMinBroadcastConnections() {
          lock.lock();
          try {
              if (minBroadcastConnections == 0) {
                  int max = getMaxConnections();
                  if (max <= 1)
                      return max;
                  else
                      return (int) Math.round(getMaxConnections() * 0.8);
              }
              return minBroadcastConnections;
          } finally {
              lock.unlock();
          }
      }
docs: Returns the number of connections that are required before transactions will be broadcast. If there aren't
  enough, {@link PeerGroup#broadcastTransaction(Transaction)} will wait until the minimum number is reached so
  propagation across the network can be observed. If no value has been set using
  {@link PeerGroup#setMinBroadcastConnections(int)} a default of 80% of whatever
  {@link PeerGroup#getMaxConnections()} returns is used.