21.2. Setting the limits

Any message larger than a certain size is considered a large message. Large messages will be split up and sent in fragments. This is determined by the parameter min-large-message-size.
The default value is 100KiB.

21.2.1. Using Core API

If the HornetQ Core API is used, the minimum large message size is specified by ClientSessionFactory.setMinLargeMessageSize. 
ClientSessionFactory factory = 
  HornetQClient.createClientSessionFactory(new 
  TransportConfiguration(NettyConnectorFactory.class.getName()), null);
factory.setMinLargeMessageSize(25 * 1024);
Section 14.3, “Configuring the transport directly from the client side” provides more information on how to instantiate the session factory.