A service object is a particularly simple kind of session object that has no associated state. Service objects have the following properties:
They are short lived. Like session objects, they have a transient lifespan.
A single service object can be used by several clients. This is because the service object does not store any client-specific state.
Service objects are insensitive to the order in which their operations are invoked.
For example, a library of mathematical functions could be implemented as a service object.
The service objects described here correspond informally to service objects as defined in the CORBA Components specification or stateless session beans as defined in the Enterprise JavaBeans specification. ...