JBoss

What is JBoss?
JBoss Application Server is an open-source platform developed by Red Hat that is used to deploy Java applications and many other software applications. You can design and deploy Java services to fit the size of your business. JBoss / Server and the suite of products are provided under a public license. With a large number of downloads per month, JBoss is the industry's most downloaded J2EE-based server.

is JBOSS still in use?
In 2013, JBoss was renamed and is now known as WildFly, but the old name is still widely used, especially by users of older versions, so we will remain JBoss for now.

JBoss features
Clustering

A computer cluster is a group of connected computers that work closely together so that they form many aspects of a single computer. Clusters are typically used to improve performance and / or availability over a single computer, and are typically much more cost-effective than individual computers with comparable speed or availability.

Load balancing

JBoss AS balances the load of the incoming request either by adding new hardware or by installing a software load balancer, eg mod_jk.

Caching

JBoss AS offers a temporary storage area where often accessed data can be stored for quick access. If the data is cached, it can be used in the future to access the cached copy, rather than retrieving or recalculating the original data

Failover

When one server goes down, control is transferred to another server. Heartbeat software is configured in JBoss AS to maintain the session.
Source: JBoss Tutorial