JBoss is an application server written in Java that can host business components developed in Java. The interface and architecture of the JBoss application server, the Java business components that can be hosted inside JBoss and various protocols by which a client application (or other business components) can interact with the business components is defined by the Enterprise JavaBeans specification. JBoss 2 is designed to be an EJB v1.1 container and server. Some parts of EJB 2.0 are supported in the 2.4.x versions, for example Message Driven Beans JBoss 3.x supports EJB v2.0 including Container Managed Persistence. The JBoss server is developed in the Open Source tradition by volunteers and sponsors using 100% Pure Java.