Lesson 6 fundamentals of internet and java programming (140 kb)

6
Fundamentals of Internet and
Java Programming

6.1 Introduction
Internet is the world's largest computer network, the network of networks,
scattered all over the world. It was created nearly 25 years ago as a project for
the U.S. Department of Defence. Its goal was to create a method for widely
separated computers to transfer data efficiently even in the event of a nuclear
attack. From a handful of computers and users in the 1960s, today the internet
has grown to thousands of regional networks that can connect millions of users.
Using internet, organisations all over the world can exchange data, people can
communicate with each other in a faster and effective way. With the help of
video conferencing over the interent, it has become possible that people can even
see each other while they are communicating. Even one can do all his shopping
sitting back at home. He does not bother to visit crowded market place for
wasting his valuable time. Gradually, shopkeepers are also interested to opt for
electronic commerce which provides them greater reach, faster and better ways
to do business over the internet. Don't get surprised, if tomorrow you come to
know that the paanwalla in your locality has started selling his paan over the
internet.
Thus, the internet has thrown up a number of technological challenges like using
the net for secure, private and fast communication as well as supporting video

102 :: Certificate in Computer Science

and 3D graphics. Given this scenario of the internet, there was an implicit need
to come up with a programming language to enable authors to incorporate
program application fragments (applets) into the web document.
Finally this gave birth to Java programming language. We will discuss about this
language in detail in later part of this lesson.

6.2 Objectives
After going through this lesson you will be in a position to :
explain various terminology used in interent
use various services provided by interent
search for desired information over internet
enjoy internet surfing
define e-mail and its various features
explain the features of World Wide Web (WWW)
explain the utility of Java programming language and its characteristics
identify the relationship between java and the internet

6.3 Internet - The History
In 1969, the U. S. Defence Department funded a project to develop a network,
which can withstand the bombing. Basically the idea was to develop a very
secured network which can work even after a nuclear attack. This project was
known as ARPANET. The proposed network was not supposed to have a central
control-which would be an obvious target. Ten years of research brought Local
Area Networks (LANs) and workstations were developed to get connected to
LAN. These workstations and LANs were then connected to the ARPANET. For
next decade the ARPANET grew and its decentralized features helped its rapid
expansion. Computers connected to ARPANET used a standard or rule to
communicate with each other. This standard used by ARPANET is known as
NCP (National Control Protocol). Protocol is a network term used to indicate

Fundamentals of Internet and Java Programming :: 103

the standard used by a network for communication. But the passing time and
rapid change in information technology suppressed NCP and brought TCP/IP
(Transmission Control Protocol/Internet Protocol) into the world of networking.
TCP converts messages into streams of packets at the source, and they are
reassembled back into messages at the destination. Internet Protocol handles
the dispatch of these packets. IP handles the addressing, and makes sure that a
packet reaches its destination through multiple nodes and even across multiple
networks with multiple standards. This flexibility of TCP/IP to handle multiple
protocols encourages other networks to get connected to ARPANET. Slowly the
ARPANET became a massive network of networks and now it is known as
'Internet'.
Internet is termed by some people as the world of largest democracy with no
government. It has no state head to control it.
Why do people want to get connected to Internet? May be because of the freedom
it provides. The internet is a rare example of a large democracy with no head of
state, no official censors, no bosses, no board of directors. Nobody controls
the Internet and in principle, any computer can speak to any other computer, as
long as it obeys the technical rules of the TCP/IP protocol. This freedom of
Internet helped it to move out of its original base in military and research
institutions, into elementary and high schools, colleges, public libraries,
commercial sectors even into the shop of a vegetable vendor.

6.4 Services of Internet - E-mail, FTP, Telnet, WWW
But what does one do with the Internet? May be four things basically mail,
discussion groups, long-distance computing, and file transfers. Internet mail
(e-mail or electronic mail) is much faster as compared to normal postal mail.
One can also send software and certain forms of compressed digital image as
an attachment. News groups or discussion groups facilitate Internet user to join
for various kinds of debate, discussion and new sharing. Long-distance
computing was an original inspiration for development of ARPANET and does
still provide a very useful service on Internet. Programmers can maintain
accounts on distant, powerful computers which execute programs. File transfers
service allows Internet users to access remote machines and retrieve programs,
data or text.


(a)

E-Mail (Electronic Mail)

E-mail or electronic mail is paperless method of sending messages, notes or
letters from one person to another or even many people at the same time via the
Internet. E-mail is very fast compared to the normal post. E-mail messages
usually take only few seconds to arrive at their destination. One can send
messages anytime of the day or night and it will get delivered immediately. You
need not have to wait for the post office to open and you don't have to get worried
about holidays. It works 24 hours a day, seven days a week. What's more, the
copy of the message you have sent will be available whenever you want to look
at it even in the middle of the night. You have the privilege of sending something
extra even such as a file, graphics, images etc. along with your e-mail. The biggest
advantage to using e--mail is that it is cheap, especially when sending messages
to other states or countries and at the same time it can be delivered to a number
of people around the world.
Although e-mail is faster and cheaper, it has many of the components of regular
mail. It allows you to compose note, get the address of the recipient and send
it. Once the mail is received and read, it can be forwarded, replied. One can
even store it for later use, or delete. In e-mail even the sender can request for
delivery receipt and read receipt from the recipient.
(i)

Features of E-mail
One-to-one or one-to-many communication
Instant communication
Physical presence of recipient is not required
Most inexpensive mail service, 24-hours a day and seven days a week
Encourages informal communication

(ii)

Components of an E-mail Address

As in the case of normal mail system, e-mail is also based upon the concept of
a recipient address. The e-mail address provides all the information required to
get a message to the recipient from anywhere in the world. Consider the
following e-mail ID


john@ hotmail.com
In the example above, "john" is the local part, which is the name of a mailbox on
the destination computer, where finally the mail will be delivered. Hotmail is
the mailserver where the mailbox "john" exists,.com is the type of organisation
on net, which is hosting the mail server.
There are six main categories;
.com Commercial institutions or organization
.edu

Educational institutions

.gov

Government site

.mil

Military site

.net

Gateways and administrative hosts

.org

Private organizations

(b)

FTP (File Transfer Protocol)

File Transfer Protocol, is an Internet utility software used to upload and download
files. It gives access to directories or folders on remote computers and allows
software, data and text files to be transferred between different kinds of
computers. FTP works on the basis of the same principle as that of Client/Server.
FTP client is a program running on your computer that enables you to talk to and
get stuff from remote computers. The FTP client takes FTP commands and sends
them as requests for information from the remote computer, known as FTP
servers. To access remote FTP server it is required but not necessary to have an
account in the FTP server. When the FTP client gets connected, FTP server asks
for the identification in terms of User Login name and password of the FTP client.
If one does not have an account in the remote FTP server, still he can connect to
the server using anonymous login. This has been properly shown in Fig. 6.1
Using anonymous login anyone can login to a FTP server and can access public
file archives, anywhere in the would, without having an account. One can easily
Login to the FTP site with the username anonymous and e-mail address as
password.
The basic objectives of FTP are


to give flexibility and promote sharing of computer programs, files and
data.
to transfer data reliably and more efficiently over network.
to encourage implicit or indirect use of remote computers using Internet.
to shield a user from variations in file storage systems among hosts.

USER
INTERFACE

USER
A

SERVER
A

FILE
SYSTEM

USER
B

SERVER
B

USER

FILE
SYSTEM
FTP CLIENT

FTP SERVER
Fig. 6.1

The basic steps in an FTP session are:
Start up your FTP client; by typing ftp on your system’s command line
c;>’ prompt (or, if you are in a Windows, double-click on the FTP icon).
Give the FTP client an address to connect to. This is the FTP server
address to which the FTP client will get connected.
Identify yourself to the FTP remote site by giving the Login Name
Give the remote site a password


Remote site will verify the Login Name/Password to allow the FTP client
to access its files.
Look directory for files in FTP server
Change Directories if required
Set the transfer mode (optional);
Get the file(s) you want; and
Quit
(c)

Telnet (Remote Computing)

Telnet or remote computing is telecommunication utility software, which uses
available telecommunication facility and allows you to become a user on a remote
computer. Once you gain access to the remote computer, you can use it for the
intended purpose. The TELNET works in a very step by step procedure. The
commands types on the client computer are sent to the local Internet Service
Provider (ISP), and then from the ISP to the remote computer that you have gained
access. Most of the ISP provides facility to TELNET into your own account
from another city and check your e-mail while you are travelling or away on
business.
The following steps are required for a TELNET session
Start up the TELNET program;
Give the TELNET program an address to connect to
Make a note of what the "escape character" is;
Log in to the remote computer;
Set the terminal emulation;
Play around on the remote computer; and
Quit.


Intext Questions 6.1
1.

Define Internet briefly.

2.

Write down the features of e-mail.

3.

What are the basic objectives of FTP?

4.

Fill in the blank.
(a)

....................... is very fast compared to the normal postal mail.

(b)

...................... is an Internet utility software used to upload and
download files.

(c)

The commands typed on the computer are sent to the local
.......................

(d)

Internet is considered as the world's largest computer network,
the ........................ of networks, scattered all over the world.

6.5 World Wide WEB (WWW)
WWW is the acronym for the World Wide Web. It is also commonly known as
'The Web'. The WWW is a hypertext based information retrieval tool. One can
easily surf the Web by jumping from one document to another using the links in
those documents. These documents can be in many formats, such as text,
graphics, animation, sound and latest is video. They may also be a combination
of all these. All the information on Internet are presented to the user as a
document or more popularly known as Web Page. All these Web Pages are linked
to each other or even to section within a Web Page and these links are known as
Hyper Links.
The tool used to view these Web Pages on Internet is known as Internet browser
or simply browser. It is a software program specifically developed to extract
information on user request from the Internet and present them as a Web Page
to the viewer. There are several browsers available in the market. However the
most popular are Internet Explorer from Microsoft and Netscape from Netscape
Inc. The process of using browser to view information on Internet is known as
Browsing or Surfing. This has been show in Fig. 6.2


Fig.6.2

(a)

Internet Address

Just like every house, every office, every location has an address every page on
the Internet has a unique address. The address is used to get the web page for
user from Internet.
Just as the address of a house or office is known as its postal address, the address
on the Internet is known as URL (Uniform Resource Locator). A typical Internet


address or URL would look like:
http://www.nios.og/computers/internet/url.htm
The URL locates a particular web page, among all the computes connected to
the Internet. The URL contains the components that specify the protocol, server,
and pathname of an item. Let us examine the URL given above (http://
www.nois.org/computers/inbtenet/url.htm).
The protocol is followed by a colon (http:) the server is preceded by two slashes
(// www.nios.org), and each segment of the pathname is preceded by a single slash
(/ computers/internet/url.htm). A protocol is a set of rules that tells the computer
how to interpret the information at that address.
The first component, the protocol, defines the manner for interpreting computer
information. Many Internet pages use HTTP (Hyper Text Transfer Protocol).
Other common Internet protocols that one might come across are FTP (File
Transfer Protocol), NEWS (Usenet news groups protocol), and GOPHER (an
alternative transfer protocol). Gopher protocol is mostly obsolete now.
The second component, the server (www.nios.edu), identifies the computer
system that stores the information you seek and is always preceded by two
slashes. A server is a computer that has information stored on it and sends it to
the client, when a request is made. Each server on the Internet has a unique address
name whose text refers to the organization maintaining the server.
The last component (/computers/internet/), defines the path within the server
where the requests item (url.htm) will be found. Most of the web pages will
have .htm or .html as their secondary or extension name.
6.5.1 How to get connected to Internet
There are various type of connectivity to get connected to Internet. They all can
be broadly classified as:
Gateway Access
Dial-up Connection
Shell Connection


TCP/IP Connection
Leased Connection
Gateway Access
Gateway Access is also known as Level-One connection. It is the access to the
Internet from a network, which is not on the Internet. The gateway allows the
two different types of networks to "talk" to each other. But the users of the
Gateway Network have limited access to the Internet. They might not be able to
use all the tools available on Internet. The local Internet Service Provider (ISP)
normally defines this limitation.
Good example of network with Level One Connectivity within India is that of
VSNL (Videsh Sanchar Nigam Limited). All access to Internet from India are
through VSNL gateway as shown in Fig. 6.4

Gateway Access
point for Internet

VSNL in India
Internet Gateway

Internet

Fig. 6.4

Dial-up Connection
‘Dail-up’ connection is also known as Level Two connection. This provides
connection to Internet through a dial-up terminal connection. The computer,
which provides Internet access is known as 'Host' and the computer that receives
the access, is ‘Client’ or ‘Terminal’. The client computer uses a modem to access
a “host” and acts as if it is a terminal directly connected to that host. So this
type of connection is also known as ‘Remote Modem Access’ connection. And
the host to which the client gets connected is actually connected to the Internet
by a full time connection as shown in Fig 6.5


Dial-up
Connection

Full Time
Connection
VSNL Internet
Host Computer

Client
Computer
Internet Gateway
Fig. 6.5

In dial-up connection to Internet, Host carries all the command that are types
on a client machine and forwards them to Internet. It also receives the data or
information from the Internet on behalf of the 'Client' and passes it to them. The
client computer acted as a 'dumb' terminal connected to remote host.
This type of connection can further be divided into two categories.
Shell Connection
In this type of Internet connection, the user will get only textual matter of a Web
Page. This connection does not support Graphics display. However the user
will be able to surf the Internet, do FTP, receive mail. Shell Accounts were the
only type of Internet access available for many years before the Internet entered
in to the world of graphics and became more users friendly.
TCP/IP Connection
Today's graphical World Wide Web browsers provides easier access with
multimedia sound and pictures. The major difference between Shell and TCP/
IP account is that shell can only display text and does not support graphics display,
whereas TCP/IP can display both. Hence TCP/IP is more popular Internet
connection. Shell accounts are slowly phasing out from the Internet scenario.
To access any of these dial-up accounts you need the followings;
Computer
Modem
Telephone Connection
Shell or TCP/IP account from the ISP
Internet client software such as Internet browser


Leased Connection
Leased connection is also known as direct Internet access or Level Three
connection. It is the secured, dedicated and most expensive, level of Internet
connection. With leased connection, your computer is dedicated and directly
connected to the Internet using high-speed transmission lines. It is on-line
twenty-four hours a day, seven days a week. Leased Internet connections are
limited to large corporations and universities who could afford the cost. These
have been clearly shown in Fig. 6.6.
VSNL
Gateway Host

Dial-up
Connection

LOCAL
HOST

Full Time
Connection

Leased Line

Local LAN Connection

Local Client

Local Client

Local Client

Local Client

Fig. 6.6

Intext Question 6.2
1.

Define World Wide Web briefly

2.

What are the various ways of connectivity to get hook on the Internet?
Explain them briefly.

3.

State whether the following statements are True or False:
(a)

www is the acronym for Word Wide Web.

(b)

In TCP/IP connection, the user will get only textual matter of a
web page.

(c)

Leased connection is also known as direct Internet access.

(d)

Dial-up connection is also known as Level Two connection.


6.6 Java and C++
Java is a derivative of C and C++: simple, familiar syntax and with fewer complex
features. It does not have many of the poorly understood, confusing and rarely
used features of C++. There are no pointers in Java only tightly bounded arrays.
This eliminates the possibility of over writing memory and corrupting data
unwittingly. Pointers have been the source of raw power in C and C++ programs
as well as the primary feature that helped introduce bugs into almost all
programs. Java is sophisticated enough to help programmers express complex
ideas using arrays and has an efficient automatic garbage collector based memory
management scheme. In addition, unlike C or C++, Java does not support
structures, enums or functions. Every programmable object is an instance of a
'class' in object oriented Java. This class definition permits both static and
dynamic inheritance and hence full reuse of code.
Java does not support multiple inheritance whose semantic and usage has been
quite controversial in other languages. Following the principles of structured
programs there are no goto statements, no automatic typecasting or operator
overloading.

6.7 Characteristic of Java
(i)

Simple and Small

Java is easily programmable, with a minimum of training, since it is based on
C++. Most of the development tools available today are huge in size and
complexity, and require powerful development platforms. But Javas's
components are comparatively very small in size, enabling construction of
compact software that can run 'stand-alone' even on small machines.
(ii)

Object Oriented

An object-oriented design enables the development of small, modular, yet selfcontained units, each of which could later be used as building block for any
specific application. It also facilitates a clean definition of interfaces and allows
'plug-and-play' features, wherein reusable software components can be
distributed easily across diverse hardware platforms. Programmers can even
attach their applications and data together, and bundle the combination as a single


entity.
Java retains many of the object oriented features and the 'look and feel' of C++.
Hence, programmers can migrate easily to Java and be productive quickly.
To be truly considered as 'object oriented' a programming language should
support a minimum of four characteristics.
Encapsulation - implements information hiding and modularity
(abstraction).
Polymorphism - the same message sent to different objects results in
behaviour that is dependent on the nature of the object receiving the
message.
Inheritance - you define new classes and behaviour based on existing
classes to obtain code re-use and code organization.
Dynamic binding - objects could come from anywhere possibly across
the network. You need to be able to send messages to objects without
having to know their specific type at the time you write your code.
Dynamic binding provides maximum flexibility while a program is
executing.
Now let us see that are objects. They are software programming models. In
your everyday life you are surrounded by objects: cars, coffee machines, trees
and so on. Software applications contain objects : buttons on user interfaces,
spreadsheets, spreadsheet cells and so on. These objects have state and behaviour.
You can represent all these things with software constructs called objects, which
can also be defined by their state and behaviour. A car can be modelled by an
object. It has state (how fast it is going, in which direction, its fuel consumption
and so on) and behaviour (starts, stops, turns etc.)
Classes are fundamental entities in Java, as they are in any object oriented
language. These classes are ways of representing certain sets of data that have
something in common and of providing an interface for the use of this data.
Encapsulating the data makes it easy to use, safe from outside interference and
also make changing the interface and data content easy. It is really simple to
reuse a great portion of code already written in Java, without bothering about


how it is implemented. Java has a huge repository of reusable code, called the
Application Programming Interface (API), which greatly simplifies basic
programming.
(iii)

Portable and Interpreted

A software application written in Java, be it a word-processor or spreadsheet, a
multimedia tool or virtual reality designer, will run perfectly on any computer,
on any platform. A Java application is a combination of a compiled and
interpreted language. The source code written by a programmer is first compiled
into Byte Code which is uniform for all machines. This Byte Code is compatible
with the Java interpreter which is termed as Java Virtual Machine. The interpreter
converts the Byte Code into specific machine code for direct execution, on any
machine to which it has been ported.
So, you may write your code anywhere and run it anywhere else. This is very
useful because most programmers worry whether their programs will run on
other systems.
(iv)

Architecture-Neutral

The Java Compiler generates an architecture-neutral object file, 'generic' Byte
Code instructions, which have nothing to do with a particular computer
architecture. This compiled code is executable on any processor, given the
presence of the Java run-time system, which will translate it into native machine
code on the fly. The same version of the software runs on all platforms,
independent of any CPU or hardware architecture, across networks.
(v)

Dynamic

By making interconnections between modules at run-time, Java completely
avoids dependency on other software components like libraries. Therefore, Java
applications are always ready-to-run, without any side-effects, irrespective of
changes or revisions that may take place in those external components.
(vi)

Distributed

Java has an extensive library of routines for easy distribution of applications as
it abides by industry standard networking protocols like TCP/IP, HTTP, FTP. Java


applications can open and access objects across the net via URLs with the same
case that programmers are used to when accessing a local file system over a
network.
(vii) Automatic Memory Management
The Java garbage collector keeps tracks of all objects generated, automatically
freeing the memory used by objects that have no further use and are not referred
to by other existing objects. This contributes enormously to making the code
robust.
(viii) Multi-Threaded
Multithreading is a way of building applications with multiple processes. Support
for multithreading enables the efficient execution of programs that potentially
have multiple threads of control. Thus, the garbage collector is efficiently run
as a background process overcoming the biggest drawback of garbage collector
based languages. Multithreading is supported via inheritable thread class
libraries. The result is better interactive response and near real-time features.
This enables Java to interface and support many features of modern operating
systems and new protocols.
Modern network based applications, such a the Hot Java WWW browser,
typically need to do several things at the same time. A user working with Hot
Java can run several animation concurrently while downloading an image and
scrolling the page, Java's multithreading capability provides the means to build
applications with many concurrent threads of activity. Multithreading thus results
in a high degree of interactivity for the end user.
(ix)

Robust

Java programs are robust because explicit memory manipulations by the
programmer are prevented.
(x)

Secured

Java programs are secured : distributed applications have to exhibit the highest
levels of security concerns. A typecode verifier in the Java interpreter ensures
that the complied code is strictly language compliant, thus trapping all malafide
modifications, more so the computer viruses parading as legal code.


6.8 How Java ignores the identity of your chip?
The chip inside your computer understands a machine code only. Since this is
too complex, programmers use a high level language. This is the source code.
This is converted into a machine code which the CPU understands. However,
the machine code varies from one chip to another. A compiler is used to execute
the conversion. However, the translation takes place in the software developer's
office and it is the translated version you buy and install in your computer.
Naturally, an application converted into the machine code for an Intel chip will
vary from the version for a Motorola chip, which will be different from the
version for a Sparc Workstation, which will have nothing in common with that
required for a Silicon Graphics machine and so on.
But, Java follows a different route. In this context, we should know more about
compiling and interpreting. Compiled programs make the entire machine code
available to the computer at one go. Everytime you use the application, every
line of machine code is installed in the memory of your computer. In contrast,
interpreted software is converted according to your commands : everytime you
want to perform a particular operation, the interpreter seeks out the appropriate
lines of source code and converts them, thus taking more time.
We have seen earlier that Java is perfectly portable across different computer
platforms. A platform is a combination of the chip and the operating system,
such as Intel-plus-Windows 95. Java is actually a combination of a compiled
and interpreted language. First, the source code is compiled using the
conventional system into a machine code. This is called byte code. The compiled
version of Java is identical for all computers. This byte code is actually
compatible with a computer that exists not as a hardware but as software : the
Java Virtual Machine (JVM).
Essentially, a JVM is nothing but an interpreter. It takes the bytecode and converts
it into the specific machine code for the actual chip of your computer. This offers
perfect portability. All that a computer, which wants to run Java applications,
will need is the appropriate interpreter which naturally will vary for different
chips. To the software developer, your computer is no longer an Intel PC, a
PowerMac, an Alpha Workstation of a Sun Spare Station; it is simply a JVM. So,
he has to write only one version of a program which has to be compiled in only


one way, liberating you from having to worry about compatibility between
software and hardware. The hardware configuration before and after Java is shown
in Fig. 6.7 and Fig. 6.8 respectively.
SOURCE CODE

Fig.6.8 Hardware Compatibility Post-Java
Fig. 6.7 Hardware compatibility Pre-Java

Fig.6.8 Hardware Compatibility Post-Java


6.9 Software Business after Java
Huge software packages with features that you many virtually never use will
become redundant. Instead, computing will be dominated by tiny disposable
applications - called applets - written for specific task only.
Applets are nothing but Java programs, usually small and having very limited
functionality, so that they can be downloaded by a browser and run. This adds
life to static Web contents with minimum effort on the part of the web page
designer.
The applets are referenced by a special tag in an HTML file - the <applet> tag.
Applets can be located anywhere, either on your local machine or somewhere
out on the Internet. It has to be specified as a URL. The location of the applet
is completely invisible to the user. The browser fetches and runs it.
Consider a stock market analyst who downloads the day's stock quotations from
around the world and runs calculations on them. Today he must have the software
on the hard disk and use the Net only as a data source. Post-Java, he will
download from the Net, not just the prices, but along with them, an applet that
lodges itself in the memory of his computer for say, half an hour. Its task will
be to perform comparisons. If the analyst needs to turn the data into bar-charts,
he has to use a different applet which will also be available on the Net. After his
use, the applet will disappear from the computer.
You need no longer worry about the high prices for the packages and their
upgrades. In the applet universe, users will need nothing more than a simple word
processing package. If you want any other occasionally used feature, you many
download for temporary use from the Net on a just-in-time-basis. You need not
buy packages for permanent ownership. Instead, you will be billed on pay-peruse basis.
Further, Java will demolish the entry barrier of expensive distribution and retail
networks that mega software vendors have created to keep small companies out
of the market. Small, low-cost programs will become viable once they are
distributed on the Net. Innovation and programming skills will dominate at the
expense of hardsell. With respect to software the pre and post Java scene is
illustrated in Fig. 6.9 and Fig. 6.10 respectively.

SOURCE CODE
COMPILER
MACHINE CODE
BIOS

OPERATING
SYSTEM

HARDWARE
Fig. 6.9 A-Software Architecture Pre-Java

SOURCE CODE
COMPILER
JAVA
INTERPRETER
BIOS

JAVA VIRTUAL
MACHINE
JUST IN TIME
COMPILER
OPERATING
SYSTEM
HARDWARE

Fig. 6.10 Software Architecture Post-Java

6.10 Java and the Internet
The Java programming language enables the Web documents authors to deliver
small application programs to anyone browsing the pages of the html documents.
The page becomes alive because it can create game score boards, execute
animated cartoons, audio files and video clippings. In addition, it changed the
way Internet and WWW worked by allowing architecturally neutral compiled
code to be dynamically loaded from anywhere in the network of heterogeneous
systems and executed transparently. The Internet usage before and after Java is
shown in Fig. 6.11 and Fig. 6.12.


Fig.6.11 Internet Usage Pre-Java

Fig. 6.12 Internet Usage Post-Java

With Java, data and programs - the twin staples of computing - do not have to be
stored on your computer anymore. They can reside anywhere on the Internet,
called up by whoever needs them and whenever they need them. The WWW
introduced millions of users to the world of the Internet. But for their charm,
most Web pages themselves are nearly as static as their book or magazine
counterparts. Although the Web is technically equipped to supply video and
sound, the user needs to have the right software to make use of them.
Java allows you to package software along with data. In other words, when you
download a video clip, you also automatically get the software needed to play it.


One thing is certain. The Web has become a powerful computer which anybody
can use, so costly desktop systems will soon be replaced by a simple computer
connected to the Internet and capable of executing any program dynamically
loaded from anywhere in the world. Companies will sell computing capabilities
over the Internet, just like our electricity boards supply us with power. In the
near future, a sizable part of our preferred activity will be over the Internet and
our success depends on our ability to adapt to and use the Internet technologies.
Future of Java
Java runs slower than conventional programming languages and the software
libraries that streamline a programmer's task are still being written for it. Java
has been a programming language for clients with a rather weak server support:
Most of the programs developed in Java are applets designed to perform small
functions like animating logos, sketching cartoon characters, etc. Application
software for client/server environments are to be developed. For these kinds
of applications, Java needs a clean, higher-level interface to databases and
servers, like ODBC (Object Data Base Connectivity) and OLE (Object Linking
and Embedding), to access data.
While these issues are being addressed, India has also jumped on the Java
bandwagon. Java is seen as a very good opportunity for the Indian software industry.
With an online connectivity to the rest of the world and a steady growth rate in
the industry, Java would probably catalyse the reorientation required for the Indian
software industry to make its mark globally.

Intext Questions 6.3
1.

Write down the various characteristics of Java Programming language.

2.

State whether the following statements are True or Flase:
(a)

There are no pointers in Java-only tightly bounded arrays.

(b)

Java does not retain many of the object oriented features and the
'look and feel' of C++.

(c)

A Java application is a combination of a compiled and interpreted


language.
(d)

Java programs are robust but lack in security.

6.11 What you have learnt
In this lesson, we have learnt the basic concept of Internet, its history and various
types of services provided by the internet. In this process, we could get an idea
about the use of e-mail and file transfer protocol. Now we have fair knowledge
to access Internet and can put it to various uses. Java programming language
along with its characteristics has been explained briefly in the last part of this
lesson.

6.12 Terminal Questions
1.

Write down a brief history of Internet.

2.

Write down the various features of e-mail.

3.

What are the basic objectives of FTP? Explain briefly.

4.

State briefly about various types of connectivity to get hooked on to
Internet

5.

What do you know about Java programming language?

6.13 Feedback to In-Text Questions
In-Text Questions 6.1
1.

Internet is considered as the network of networks, scattered all over the
world. It is undoubtedly the world's largest network carrying information
on almost any subject under the sun.

2.

Features of e-mail are:
(a)

One-to-one or one-to-many communication.

(b)

Instant communication


(c)
(d)

Most inexpensive mail service, 24 hours a day and seven days a
week.

(e)
3.

Physical presence of recipient not required

Encourages informal communication

Basic objectives of FTP are:
(a)

(b)

to transfer data reliably and more efficiently over network.

(c)

to encourage implicit or indirect usae of remote computers using
Internet.

(d)

to shield a user from variations in file storage systems among
hosts.

(a)

E-mail (b)

(d)

4.

to give flexibility and promote sharing of computer programs,
files and data.

network

FTP

(c)

ISP

1.

The world wide web or simply the web is built on top of the Internet. It is
hypertext based information retrieval tool.

2.

Various ways of connectivity are:
(a)
(b)

Dial-up Connection

(c)

Shell Connection

(d)

TCP/IP Connection

(e)
3.

Gateway Access

Leased Connection

(a) False

(b) Flase (c) True (d) True


1.

Various characteristics are:
(a)
(b)

Object oriented

(c)

Portable and interpreted

(d)

Dynamic and distributed

(e)
2.

Simple and small

Robust and Secure

(a) True (b) False (c) True (d) False

Lesson 6 fundamentals of internet and java programming (140 kb)

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