The application server, being a Java process, requires a Java virtual machine (JVM) to run, and to support the Java applications running on it. As part of configuring an application server, you can fine-tune settings that enhance system use of the JVM.
The performance of some applications is limited by the amount of memory that the JVM can address. In particular, multithreaded programs that allocate heavily often bottleneck in garbage collection, and the total time spent in garbage collection can gener
X. Yang, S. Blackburn, D. Frampton, J. Sartor, and K. McKinley. Proceedings of the 2011 ACM International Conference on Object Oriented Programming Systems Languages and Applications, page 307--324. ACM, (2011)