Adding Java Instances
When the number of client requests to the AS Java is large, you may need to resize your cluster by installing new Java Instances.
You install additional Java instances on different physical machines, thus adding more hardware resources and improving the failover capabilities of your system.
You have installed the basic components of the cluster.
To install an additional Java instance, refer to Master Guide/ Installation Guide for SAP NetWeaver 7.1 Composition Environment at service.sap.com/instguides.

Scaling the cluster by adding a Java instance