<specification, business, programming> (EJB) A server
-side component architecture
for writing reusable business logic and portable enterprise
EJB is the basis of Sun
's Java 2 Platform, Enterprise Edition
Enterprise JavaBean components are written entirely in Java
and run on any EJB compliant server.
They are operating system
, and middleware
independent, preventing vendor lock-in
EJB servers provide system-level services (the "plumbing") such as transactions, security, threading
, and persistence
The EJB architecture is inherently transactional, distributed, multi-tier, scalable, secure, and wire protocol neutral - any protocol
can be used: IIOP
EJB 1.1 requires RMI
for communication with components.
EJB 2.0 is expected to require support for RMI/IIOP.
EJB applications can serve assorted clients: browsers, Java, ActiveX
EJB can be used to wrap legacy systems.
EJB 1.1 was released in December 1999.
EJB 2.0 is in development.
Sun claims broad industry adoption.
30 vendors are shipping server products implementing EJB.
Supporting vendors include IBM
, Sybase, Borland, Oracle, and Symantec
An alternative is Microsoft's MTS (Microsoft Transaction Server).