DEPARTMENT OF INFORMATION TECHNOLOGY
IT1451 –WEB TECHNOLOGY
UNIT – III Two Marks with Answers
SUBJECT CODE : IT1451
SUBJECT NAME:WEB TECHNOLOGY
43. Define packet switched networks.
Packet switched network means that data traveling on the network is broken into chunks called packets and each packet is handled separately.
44. Define socket.
The socket is a software abstraction used to represent the terminals of a connection between two machines or processes.
45. What are the basic operations of client sockets?
Connect to a remote machine
Close a connection
46. What are the basic operations of Server socket?
Bind to a port
Listen for incoming data
Accept connections from remote machines on the bound port
47. List all the socket classes in java.
Socket ServerSocket Datagram Socket Multicast Socket Secure sockets
48.What the Socket Object does?
Socket object is the java representation of a TCP connection when a socket is created; a connection is opened to the specified destination.
49. What is meant by Server Socket?
ServerSocket represents a listening TCP connection. Once an incoming connection is requested, the ServerSocket object will return a Socket object representing the connection.
50. What do you mean by DatagramSocket and DatagramPacket?
DatagramSocket represents a connectionless datagram socket. This class works with the
DatagramPacket class to provide for communication using the UDP protocol.
51. Write a note on Connect Exception.
This exception is raised when a connection is refused at the remote host. (ie, no process is listening on that port).
52. What is a multicast socket?
Multicasting sends data from one host to many different hosts, which are in the multicast group.
53. What is multicast address and the range of address?
A multicast address is the address of a group of hosts called a multicast group. Multicast addresses are IP addresses in the range 220.127.116.11 to 18.104.22.168
54. What are the different types of IP addresses?
Unicast address: It is used for transmitting a message to single destination node
Multicast address: It delivers a message to a group of destination nodes, which are necessarily in the same sub network.
Broadcast address: It transmits a message to all nodes in a sub network.
55. What is meant by protocol handler?
Protocol handlers are used to retrieve the web objects using application specific protocols. The protocols are specified in the URL referencing the object.
56. How are the protocol handlers implemented?
Four different classes in the java.net package implement the protocol handlers:
57. What are the methods for parsing URLs?
1. parseURL(URL u, String spec, int start, int limit)- splits the URL into parts
2. setURL(URL u, Sring protocol, String host, int port, String file, String ref) -assigns values to the URL’s fields.
58. What is content handler?
Content handlers are used to retrieve objects via an URLConnection object.
59. What is Remote Method Invocation?
The Remote Method Invocation is application-programming interface that allows java objects on different hosts communicate with each other.
60. What do you mean by remote object?
Objects that have methods that can be called across virtual machines are remote objects.
61. Define serialization.
It is the process of converting a set of object instances that contain references to each other into a linear stream of bytes, which can then be through a socket. It is the mechanism used by RMI to pass objects between Java Virtual Machines.
62. What are the responsibilities of stub?
A stub for a remote object is the client side proxy for the remote object. A client side stub is responsible for:
1.Initiating a call to the remote object
2.Marshaling arguments to a marshal stream
3.Informing the remote reference layer that the call should be invoked
4.Unmarshaling the return value or exception from a marshal stream
63. What is the role of skeleton in RMI?
A skeleton for a remote object is a server side entity that contains a method which dispatches calls to the actual remote object implementation. The skeleton is responsible for
1.Unmarshaling arguments from the marshal stream.
2.Making the up-call to the actual remote object.
3.Marshalling the return value of the call to an exception onto the Marshall stream
64. List down the layers of RMI architecture.
2.Remote reference layer
65. Define Object Activation.
Object Activation is mechanism, which allows a java object to be bound and then activated at some later data simply by referencing the object through the Registry.
66. Write down the Socket object methods to get information about a socket.
1. getInetAddress ()- displays which remote host the Socket is connected to
2. getPort () -displays which port the Socket is connected to on the remote host.
3. getLoca1Port ()- to find the port number for the local end of a connection
4. getLocalAddress () -tells you which network interface a socket is bound to.
67. What operations Multicast Socket Perform?
1. Join a multicast group
2. Send data to the members of the group
3. Receive data from the group
4. Leave the multicast group