How does the race
It occurs when two or more processes are reading or
writing some shared data and the final result depends on
who runs precisely when.
What is multiprogramming?
Multiprogramming is a rapid switching of the CPU back
and forth between processes.
Name the seven layers of the OSI Model and describe them
Physical Layer - covers the physical interface between
devices and the rules by which bits are passed from one
Data Link Layer - attempts o make the physical link
reliable and provides the means to activate, maintain,
and deactivate the link.
Network Layer - provides for the transfer of information
between end systems across
some sort communications network.
Transport Layer - provides a mechanism for the exchange
of data between end system.
Session Layer - provides the mechanism for controlling
the dialogue between applications in end systems.
Presentation Layer - defines the format of the data to
be exchanged between applications and offers application
programs a set of data transformation services.
Application Layer - provides a means for application
programs to access the OSI environment.
What is the difference between TCP and UDP?
TCP and UDP are both transport-level protocols. TCP is
designed to provide reliable communication across a
variety of reliable and unreliable networks and
UDP provides a connectionless service for
application-level procedures. Thus, UDP is basically an
unreliable service; delivery and duplicate protection
are not guaranteed.
What does a socket consists of?
The combination of an IP address and a port number is
called a socket.
What are some advantages and disadvantages of Java
Advantages of Java Sockets:
Sockets are flexible and sufficient. Efficient socket
based programming can be easily implemented for general
Sockets cause low network traffic. Unlike HTML forms and
CGI scripts that generate and transfer whole web pages
for each new request, Java applets can send only
necessary updated information.
Disadvantages of Java Sockets:
Security restrictions are sometimes overbearing because
a Java applet running in a Web browser is only able to
establish connections to the machine where it came from,
and to nowhere else on the network
Despite all of the useful and helpful Java features,
Socket based communications allows only to send packets
of raw data between applications. Both the client-side
and server-side have to provide mechanisms to make the
data useful in any way.
Since the data formats and protocols remain application
specific, the re-use of socket based implementations is
What is the difference between a NULL pointer and a void
A NULL pointer is a pointer of any type whose value is
zero. A void pointer is a pointer to an object of an
unknown type, and is guaranteed to have enough bits to
hold a pointer to any object. A void pointer is not
guaranteed to have enough bits to point to a function
(though in general practice it does).
What is encapsulation technique?
ANSWER: Hiding data within the class and making it
available only through the methods. This technique is
used to protect your class against accidental changes to
fields, which might leave the class in an inconsistent