This figure demonstrates OC4J processes in their respective islands within
the cluster. The OC4J islands, designated within the shaded area, crosses
application server instances to endure that the OC4J processes exist on
more than a single host to avoid the single point of failure. Within the
OC4J home instance, the OC4J processes are grouped into two islands, default-island
and second-island, to handle the load of state replication with
the OC4J cluster.