Single instance features: Each Oracle Application Server instance has built-in features, such as process death detection and restart, configuration cloning, and intelligent routing, to improve availability.

Clustering: A cluster is a set of application server instances that are configured to act in concert, providing increased availability and scalability. A cluster can span multiple hosts, leveraging the power of multiple CPUs while continuing to function despite the loss of any single instance or host.

Load balancing: You can use Web Cache or an external load balancer in front of a set of instances to route requests to the most available instances.