• wikipedia: https://en.wikipedia.org/wiki/Enterprise_JavaBeans
• EJB is a component which will be deployed to application server
  • technically, it is a Java object which extends EJB class
• EJB class provides some services including:
  • Transaction processing
  • Integration with the persistence services offered by the Java Persistence API (JPA)
  • Concurrency control
  • Event-driven programming using Java Message Service and Java EE Connector Architecture
  • Asynchronous method invocation
  • Job scheduling
  • Naming and directory services (JNDI)
  • Interprocess Communication using RMI-IIOP and Web services
  • Security (JCE and JAAS)
  • Deployment of software components in an application server
• Provides transactional integrity -- ensures that some service (which includes call chains across network) to rollback when there is a failure