Interview Questions and Answers

In client-server technology / architecture, a server responds to a remote client. A call back is a method invocation from one application (Application A) from another application (Application B), as a result of action that was performed by the Application B earlier. The Application A may run on a client and the Application may run on a server. To perform the call back mechanism the system that Application A runs acts as a Server and that of the Application B runs acts as a client.

Object Activation is a process of providing persistent references to the objects. It also includes the managing the execution of implementing of objects. RMI activates the objects for the execution as and when needed. The appropriate execution is initiated inside the appropriate JVM when the activatable remote object is accessed which is not currently running.

The difference between unicast and multicast is that in unicast approach the sender sends the data stream to a single receiver at a time. Thus there is one to one communication.

In a multicast the sender and the interested receivers communicate. This is one to many communication. This communication can take place between data terminals spread across various LANs too.